Base environment configuration module (#931)

* The base envconfig module to be used by lang-SDKs

* linting

* add pr review - use enum for path/data inputs, validate against providing both, read env vars from hashmap instead of trait env lookup

* formatting & linting

Author: THardy98

core-api/Cargo.toml

@@ -14,15 +14,20 @@ categories = ["development-tools"]
 
 [features]
 otel_impls = ["dep:opentelemetry"]
+envconfig = ["dep:toml", "dep:serde", "dep:dirs", "dep:anyhow"]
 
 [dependencies]
+anyhow = { version = "1.0", optional = true }
 async-trait = "0.1"
+dirs = { version = "5.0", optional = true }
 derive_builder = { workspace = true }
 derive_more = { workspace = true }
 opentelemetry = { workspace = true, optional = true }
 prost = { workspace = true }
+serde = { version = "1.0", features = ["derive"], optional = true }
 serde_json = "1.0"
 thiserror = { workspace = true }
+toml = { version = "0.8", optional = true }
 tonic = { workspace = true }
 tracing-core = "0.1"
 url = "2.3"
@@ -33,3 +38,6 @@ version = "0.1"
 
 [lints]
 workspace = true
+
+[dev-dependencies]
+tempfile = "3.8"