Link to AWS Lambda Instructions from OTLP Ingestion Page

[brett0000FF]

What does this PR do? What is the motivation?

• Users are looking for AWS Lambda content on OTLP Ingestion by the Datadog Agent.
• Add new tab with brief content and link to serverless docs for more info.

Merge instructions

• [ ] Please merge after reviewing

Additional notes

[github-actions[bot]]

Preview links (active after the build_preview check completes)

Modified Files

• https://docs-staging.datadoghq.com/brett0000FF/DOCS-8900/opentelemetry/interoperability/otlp_ingest_in_the_agent