Add CommTagAttribute for metric code generator

[BowenYang666]

For Metrics generation, we can add some common tag that can apply to all metrics within this class.

1.

With common tags, metrics defined in this class will all have the common dimension with same value, it's helpful when we want to add some static values.
example code:

[CommonTag("Category", "Http")]
[CommonTag("MetricVersion", "v1")]
 static partial class Metric
 {
    [Counter("RequestName", "RequestStatusCode")]
    static partial RequestCounter CreateRequestCounter(Meter meter);
}

public void Record(long value, object? RequestName, object? RequestStatusCode)
{
    var tagList = new global::System.Diagnostics.TagList
    {
        new global::System.Collections.Generic.KeyValuePair<string, object?>("RequestName", RequestName),
        new global::System.Collections.Generic.KeyValuePair<string, object?>("RequestStatusCode", RequestStatusCode),
        new global::System.Collections.Generic.KeyValuePair<string, object?>("Category", "Http"),
        new global::System.Collections.Generic.KeyValuePair<string, object?>("MetricVersion", "v1"),
    };

    _histogram.Record(value, tagList);
}

2.

When it comes to geneva metrics, we can use this feature to send to different account and namespace.

[CommonTag("_microsoft_metrics_namespace", "TestNamespace")]

It will be even greater if we can create a new attribute for geneva account and namespace attribute. Since opentelemetry doesn't support export different metrics to different account and namespace, this maybe a solution.
So with genevaAttribute, the code may look like this:

[GenevaTag(genevaAccount: "testAccount", genevaNamespace: "testNamespace")]

then we can generate the code and add account and namespace override in Record()

            var tagList = new global::System.Diagnostics.TagList
            {
                new global::System.Collections.Generic.KeyValuePair<string, object?>("_microsoft_metrics_namespace", "testNamespace"),
            };

            _histogram.Record(value, tagList);