Add BatchUnsampledSpanProcessor for exporting unsampled spans

[mxiamxia]

Description of changes:

1. Implemented a new AwsBatchUnsampledSpanProcessor to only export unsampled spans(TraceFlags.SAMPLED !==1)
2. Registered it as an additional SpanProcessor for TraceProvider
3. Add different Prefixes for sampled/unsampled OTel span when sending to FluxPump
   • Sampled Spans Prefix - T1S
   • Unsampled Spans Prefix - T1U

Test
X-Ray data example

{
    "Id": "1-66e11092-767bc32c5717c925604e37e3",
    "Duration": 0.158,
    "LimitExceeded": false,
    "Segments": [
        {
            "Id": "5a5e9957e3a068ef",
            "Document": {
                "id": "5a5e9957e3a068ef",
                "name": "aws-opentelemetry-distro-nodejs",
                "start_time": 1726025874.375,
                "trace_id": "1-66e11092-767bc32c5717c925604e37e3",
                "end_time": 1726025874.527,
                "parent_id": "5ff5cfd8f1c6ed59",
                "http": {
                    "response": {
                        "status": 200
                    }
                },
                "aws": {
                    "request_id": "e4ac3af9-7538-4b8c-84c8-36d154378813"
                },
                "origin": "AWS::Lambda",
                "resource_arn": "arn:aws:lambda:us-west-2:252610625673:function:aws-opentelemetry-distro-nodejs"
            }
        },
        {
            "Id": "30e074d0013a9b6f",
            "Document": {
                "id": "30e074d0013a9b6f",
                "name": "aws-opentelemetry-distro-nodejs/default",
                "start_time": 1726025874.369,
                "trace_id": "1-66e11092-767bc32c5717c925604e37e3",
                "end_time": 1726025874.527,
                "http": {
                    "request": {
                        "url": "https://aixsrfz8n8.execute-api.us-west-2.amazonaws.com/default",
                        "method": "GET",
                        "user_agent": "curl/8.7.1",
                        "client_ip": "205.251.233.233",
                        "x_forwarded_for": true
                    },
                    "response": {
                        "status": 200,
                        "content_length": 0
                    }
                },
                "aws": {
                    "xray": {
                        "sampling_rule_name": "Default"
                    },
                    "api_gateway": {
                        "account_id": "252610625673",
                        "rest_api_id": "aixsrfz8n8",
                        "stage": "default",
                        "request_id": "41da0ef6-b16c-45e9-9334-a11347f5dec7"
                    }
                },
                "annotations": {
                    "aws:api_id": "aixsrfz8n8",
                    "aws:api_stage": "default"
                },
                "metadata": {
                    "default": {
                        "extended_request_id": "d6-G6FsovHcEMoQ=",
                        "request_id": "41da0ef6-b16c-45e9-9334-a11347f5dec7"
                    }
                },
                "origin": "AWS::ApiGateway::Stage",
                "resource_arn": "arn:aws:apigateway:us-west-2::/restapis/aixsrfz8n8/stages/default",
                "subsegments": [
                    {
                        "id": "5ff5cfd8f1c6ed59",
                        "name": "Lambda",
                        "start_time": 1726025874.371,
                        "end_time": 1726025874.527,
                        "http": {
                            "request": {
                                "url": "https://lambda.us-west-2.amazonaws.com/2015-03-31/functions/arn:aws:lambda:us-west-2:252610625673:function:aws-opentelemetry-distro-nodejs/invocations",
                                "method": "ANY"
                            },
                            "response": {
                                "status": 200,
                                "content_length": 120
                            }
                        },
                        "aws": {
                            "function_name": "aws-opentelemetry-distro-nodejs",
                            "region": "us-west-2",
                            "operation": "Invoke",
                            "resource_names": [
                                "aws-opentelemetry-distro-nodejs"
                            ]
                        },
                        "namespace": "aws"
                    }
                ]
            }
        },
        {
            "Id": "7197ce026d312a49",
            "Document": {
                "id": "7197ce026d312a49",
                "name": "aws-opentelemetry-distro-nodejs",
                "start_time": 1726025874.3797677,
                "trace_id": "1-66e11092-767bc32c5717c925604e37e3",
                "end_time": 1726025874.5265381,
                "parent_id": "5a5e9957e3a068ef",
                "aws": {
                    "account_id": "252610625673",
                    "function_arn": "arn:aws:lambda:us-west-2:252610625673:function:aws-opentelemetry-distro-nodejs",
                    "cloudwatch_logs": [
                        {
                            "log_group": "/aws/lambda/aws-opentelemetry-distro-nodejs"
                        }
                    ],
                    "resource_names": [
                        "aws-opentelemetry-distro-nodejs"
                    ]
                },
                "origin": "AWS::Lambda::Function",
                "subsegments": [
                    {
                        "id": "ca73bcb9d61476de",
                        "name": "Invocation",
                        "start_time": 1726025874.3798523,
                        "end_time": 1726025874.5261395,
                        "aws": {
                            "function_arn": "arn:aws:lambda:us-west-2:252610625673:function:aws-opentelemetry-distro-nodejs"
                        }
                    },
                    {
                        "id": "4153b4f45ff3b1e8",
                        "name": "Overhead",
                        "start_time": 1726025874.5261652,
                        "end_time": 1726025874.5264673,
                        "aws": {
                            "function_arn": "arn:aws:lambda:us-west-2:252610625673:function:aws-opentelemetry-distro-nodejs"
                        }
                    }
                ]
            }
        },
        {
            "Id": "ae60d7baedc1cfb5",
            "Document": {
                "id": "ae60d7baedc1cfb5",
                "name": "aws-opentelemetry-distro-nodejs",
                "start_time": 1726025874.38,
                "trace_id": "1-66e11092-767bc32c5717c925604e37e3",
                "end_time": 1726025874.5246706,
                "parent_id": "ca73bcb9d61476de",
                "aws": {
                    "trace.flag.unsampled": true,
                    "is.local.root": true
                },
                "annotations": {
                    "span.kind": "SERVER"
                },
                "metadata": {
                    "faas.id": "arn:aws:lambda:us-west-2:252610625673:function:aws-opentelemetry-distro-nodejs",
                    "cloud.account.id": "252610625673",
                    "faas.execution": "e4ac3af9-7538-4b8c-84c8-36d154378813"
                },
                "subsegments": [
                    {
                        "id": "328592d80ebf7e72",
                        "name": "GET",
                        "start_time": 1726025874.483,
                        "end_time": 1726025874.5237389,
                        "aws": {
                            "trace.flag.unsampled": true,
                            "local.operation": "aws-opentelemetry-distro-nodejs",
                            "is.local.root": false
                        },
                        "annotations": {
                            "span.kind": "CLIENT"
                        },
                        "metadata": {
                            "net.transport": "ip_tcp",
                            "net.peer.name": "jsonplaceholder.typicode.com",
                            "http.status_code": 200,
                            "net.peer.port": 443,
                            "http.target": "/todos/1",
                            "http.flavor": "1.1",
                            "http.url": "https://jsonplaceholder.typicode.com/todos/1",
                            "http.status_text": "OK",
                            "net.peer.ip": "104.21.59.19",
                            "http.method": "GET",
                            "http.host": "jsonplaceholder.typicode.com:443"
                        },
                        "namespace": "remote"
                    },
                    {
                        "id": "6d998c5cf661c0ec",
                        "name": "S3.ListBuckets",
                        "start_time": 1726025874.381,
                        "end_time": 1726025874.4829986,
                        "aws": {
                            "signature.version": "s3",
                            "service.name": "Amazon S3",
                            "trace.flag.unsampled": true,
                            "local.operation": "aws-opentelemetry-distro-nodejs",
                            "service.api": "S3",
                            "region": "us-west-2",
                            "is.local.root": false,
                            "service.identifier": "s3",
                            "operation": "listBuckets",
                            "request.id": "XWEGH4NV5PMQZEHV"
                        },
                        "annotations": {
                            "span.kind": "CLIENT"
                        },
                        "metadata": {
                            "http.status_code": 200,
                            "rpc.service": "S3",
                            "rpc.method": "ListBuckets",
                            "rpc.system": "aws-api"
                        },
                        "namespace": "aws",
                        "subsegments": [
                            {
                                "id": "5b8e13800550b551",
                                "name": "GET",
                                "start_time": 1726025874.381,
                                "end_time": 1726025874.4812143,
                                "aws": {
                                    "trace.flag.unsampled": true,
                                    "local.operation": "aws-opentelemetry-distro-nodejs",
                                    "is.local.root": false,
                                    "sdk.descendant": "true"
                                },
                                "annotations": {
                                    "span.kind": "CLIENT"
                                },
                                "metadata": {
                                    "net.transport": "ip_tcp",
                                    "net.peer.name": "s3.us-west-2.amazonaws.com",
                                    "http.status_code": 200,
                                    "net.peer.port": 443,
                                    "http.target": "/",
                                    "http.flavor": "1.1",
                                    "http.url": "https://s3.us-west-2.amazonaws.com/",
                                    "http.status_text": "OK",
                                    "net.peer.ip": "52.218.178.96",
                                    "http.method": "GET",
                                    "http.host": "s3.us-west-2.amazonaws.com:443"
                                },
                                "namespace": "remote"
                            }
                        ]
                    }
                ]
            }
        },
        {
            "Id": "1c146cef33e14019",
            "Document": {
                "id": "1c146cef33e14019",
                "name": "GET",
                "start_time": 1726025874.381,
                "trace_id": "1-66e11092-767bc32c5717c925604e37e3",
                "end_time": 1726025874.4812143,
                "parent_id": "5b8e13800550b551",
                "inferred": true
            }
        },
        {
            "Id": "2bccb63c011d05ec",
            "Document": {
                "id": "2bccb63c011d05ec",
                "name": "GET",
                "start_time": 1726025874.483,
                "trace_id": "1-66e11092-767bc32c5717c925604e37e3",
                "end_time": 1726025874.5237389,
                "parent_id": "328592d80ebf7e72",
                "inferred": true
            }
        }
    ]
}

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.