Audit opentelemetry source

[spencergilbert]

• Exercise the component locally
• Refresh configuration documentation: ensure it is accurate and proofread
• Update examples to be real-world
• Update component status (beta or stable)
• Ensure vector generate generates a valid configuration - blocked by [bug]vector generate output that includes components without default outputs aren't functional #13982
• Document any deprecated metrics on the website

Discovered:

• [bug]vector generate output that includes components without default outputs aren't functional #13982
• [opentelemetry source] Missing source_type field #13932
• [opentelemetry source] Incorrect message when body is an ArrayValue #13926
• [opentelemetry source,opentelemetry sink] look into using opentelemetry-rust/opentelemetry-proto instead of our own lib #13963