parametric: Adds a feature to track the parity for parametric endpoints

[mabdinur]

Motivation

Introduces parametric_endpoint_parity feature.

The goal of the parametric_endpoint_parity feature is to:

• Track which parametric endpoints are implemented in each language
• Document and assert the expected input and outputs for each parametric endpoint
• Future proofing: Catch unexpected regressions/modifications in parametric endpoints
• Track which parametric apps are incomplete and require additional work
• Require all future parametric endpoints to have one test case in parametric_endpoint_parity.py

Changes

• Adds unit tests/documentation for supported parametric endpoints
• Updates the python parametric app to ensure it is fully up to spec. This will be the reference implementation for all endpoints.
• Marks some parametric endpoints for removal
• Marks some arguments in parametric endpoints for removal
• Includes a link to the parametric_endpoint_parity tab in the feature parity dashboard in contributing docs. Before introducing new tests developers should be aware of the health and availability of parametric endpoints.

Next steps

• Fix all failing tests in test_parametric_endpoints.py
• Remove:
  • _TestSpan.span_get_name, _TestSpan.span_get_resource, _TestSpan.span_get_meta, _TestSpan.span_get_metric interfaces/endpoints. These operations are not supported in most languages. Tests should be refactored to use the test agent to retrieve span data.
  • _TestOtelSpan.get_attribute, _TestOtelSpan.get_name, _TestOtelSpan.get_links` interfaces and parametric endpoints. These operations are not supported in the opentelemetry-api. Tests should be refactored to use the test agent to retrieve span data.
  • APMLibrary.current_span and APMLibrary.otel_current_span interfaces/endpoints. Retrieving the current active span is not possible in all parametric apps. Many parametric apps are multi-threaded do not store the "current span" as the active span. Spans should always be retrieved by span_id.
  • APMLibrary.http_client_request endpoint. This endpoint only exists in 1 or 2 apps. It does not test a span/tracer api. The make_distinct_call weblog endpoint should be used instead.
  • http_headers, origin, and links arguments from trace/span/start. Most libraries do not support initializing a datadog span with these values. We will provide a alternative mechanisms to apply these values to spans: parametric: Ensure start span endpoints align with the spec #3300

Workflow

1. ⚠️ Create your PR as draft ⚠️
2. Work on you PR until the CI passes (if something not related to your task is failing, you can ignore it)
3. Mark it as ready for review
   • Test logic is modified? -> Get a review from RFC owner. We're working on refining the codeowners file quickly.
   • Framework is modified, or non obvious usage of it -> get a review from R&P team

🚀 Once your PR is reviewed, you can merge it!

🛟 #apm-shared-testing 🛟

Reviewer checklist

• If PR title starts with [<language>], double-check that only <language> is impacted by the change
• No system-tests internal is modified. Otherwise, I have the approval from R&P team
• CI is green, or failing jobs are not related to this change (and you are 100% sure about this statement)
• A docker base image is modified?
  • the relevant build-XXX-image label is present
• A scenario is added (or removed)?
  • Get a review from R&P team