feat(aap): update tags on inferred spans for API Gateway

[florentinl]

What does this PR do?

It updates tags for API Gateway Rest Proxy and HTTP API inferred spans:

From the RFC:

Motivation

This PR implements RFC-1081.

The goal is be able to use API Gateway lambda inferred spans for endpoint discovery and correlation in the AppSec API Catalog.

Testing Guidelines

• unit tests have been updated to reflect the expected behavior
• snapshot tests: TODO
• system-tests: inprogress: http://github.com/DataDog/system-tests/pull/5830

Additional Notes

• _dd.appsec.* meta and metrics are set in ddtrace directly: feat(aap): report AAP on lambda inferred spans dd-trace-py#15511

Types of Changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog
• This PR passes the integration tests (ask a Datadog member to run the tests)