feat: Add Observability Runtime Interfaces

[syall]

Issue #

awslabs/aws-sdk-swift#696

Description of changes

Standardizes the Observability client runtime configuration and interfaces:

• Context
• Logging
• Metrics
• Tracing

Also, adds the default implementation of TelemetryProvider.

This PR is only additive besides the moved Logging source files.

Testing

$ swift --version
swift-driver version: 1.87.3 Apple Swift version 5.9.2 (swiftlang-5.9.2.2.56 clang-1500.1.0.2.5)
Target: arm64-apple-macosx14.0

$ swift build && swiftlint --fix && swiftlint
# Succeeds!

Scope

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[sichanyoo]

Additions look great, but given that these protocols are going to be semi-permanent & end-users are expected to implement them for customizations, I think the public protocols and methods in them need documentation comments. E.g.,

/// Brief overview on method usage.
///
/// - Parameter: input : Comment
/// - Returns: ReturnABC : Comment
func fillerFunc(input: ParamABC) -> ReturnABC

[sichanyoo]

Mostly questions and some small suggestions.

[jbelkins]

Only a few superficial changes to make. I will put these in & merge.

[jbelkins]

I entered some cleanup changes myself. This change is now good to merge, per conversation with @syall.