docs/examples: Shift rst files into example folders

[phlax]

trafficstars

Step towards #32737

Commit Message: Additional Description: Risk Level: Testing: Docs Changes: Release Notes: Platform Specific Features: [Optional Runtime guard:] [Optional Fixes #Issue] [Optional Fixes commit #PR or SHA] [Optional Deprecated:] [Optional API Considerations:]

[phlax]

/docs

[repokitteh-read-only[bot]]

Docs for this Pull Request will be rendered here:

https://storage.googleapis.com/envoy-pr/34429/docs/index.html

The docs are (re-)rendered each time the CI envoy-presubmit (precheck docs) job completes.

:cat:

Caused by: a https://github.com/envoyproxy/envoy/pull/34429#issuecomment-2141526227 was created by @phlax.

see: more, trace.

[phlax]

/retest