Feat(lambda): Refactor Extension to a Unified Collector-Based Layer

[bardabun]

This PR introduces Combined Layers that bundle language instrumentation and a custom embedded OpenTelemetry Collector into a single Lambda layer, alongside a refactored, modernized collector pipeline and build system.

Key changes

• New telemetryapireceiver: Converts AWS Telemetry API platform events into OTel logs, metrics, and traces.
• Unified pipeline: All telemetry (platform + app) flows through one collector pipeline with sensible defaults.
• Combined Layers: Single-layer deployment for Python, Node.js, Java, Ruby, and Go (collector-only for Go).
• Build system: Production-ready build scripts per language:
  • python: python/src/build-combined.sh
  • nodejs: nodejs/packages/layer/build-combined.sh
  • java: java/build-combined.sh
  • ruby: ruby/build-combined.sh
  • go: go/build-combined.sh
• Documentation: Additive updates to each language README (no major rewrites) with Combined Layer usage and environment variables (Required vs Optional).

[8naama]

Nice work! 🎉

I've left some comments, specifically about fork considerations, I think to make merging in the future simpler - we should minimize the amount of changes to existing files where possible. Do you think all changes are worth the trade off?