docs: start doc for distributed tracing and logs guidance

[cijothomas]

Adds initial guidance docs for logs and traces in the OpenTelemetry Rust ecosystem.

• docs/logs.md — marked Stable.
• docs/traces.md — marked Work-In-Progress (OpenTelemetry Tracing in this repo is not yet stable).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.8%. Comparing base (8db5a12) to head (a9c02fa).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #3122     +/-   ##
=======================================
- Coverage   82.8%   82.8%   -0.1%     
=======================================
  Files        130     130             
  Lines      27289   27289             
=======================================
- Hits       22622   22621      -1     
- Misses      4667    4668      +1     

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[github-actions]

Thank you for your contribution! This PR has been automatically marked as stale because it has not had activity in the last 14 days. This may be due to a delay in review on our side or awaiting a response from you; either is fine, and we appreciate your patience.

It will be closed in 14 days if no further activity occurs. Pushing a new commit or leaving a comment will remove the stale label and keep the PR open.

[cijothomas]

Marked ready for review. @davidbarsky @scottgerring — would appreciate another look; the open threads from your earlier review should now be addressed (intro now leads with a thesis, level-of-detail trimmed). @alessandrobologna — courtesy ping; the tracing-opentelemetry framing is now neutral and I added the tracing-http-propagator example to See Also per your suggestion.

[scottgerring]

Some nits!

[scottgerring]

I think we can be more succinct here:

Suggested change

	provides a bridge. It is maintained outside the OpenTelemetry project and
	is not part of this repo; we point to it so users are aware of the option
	in the broader ecosystem.
	provides a bridge. It is maintained outside the OpenTelemetry project and is not part of this repo.

[cijothomas]

@scottgerring Addressed your comments, thank you!

[scottgerring]

🚢

[cijothomas]

@open-telemetry/rust-maintainers Please review. I'd like to get more eyes before merging this.