[Serve] Add ray serve request timeout to config

[GeneDer]

Why are these changes needed?

Currently the only way to config the http request timeout is through setting up RAY_SERVE_REQUEST_PROCESSING_TIMEOUT_S (or yet to deprecated SERVE_REQUEST_PROCESSING_TIMEOUT_S) environment variables. This PR adds new config request_processing_timeout to the http_options in serve config and use it as the timeout in the http requests.

• added RAY_SERVE_REQUEST_PROCESSING_TIMEOUT_S deprecation message
• added request_processing_timeout to HTTPOptionsSchema for documentation should also generated at https://docs.ray.io/en/master/serve/api/doc/ray.serve.schema.HTTPOptionsSchema.html#ray.serve.schema.HTTPOptionsSchema.request_processing_timeout when merged
• Fixed a small bug in when running serve run with config files, the http_options are not picked up
• Also did a manual test locally running serve run test_config.yaml and seeing the request_processing_timeout in the config getting respected

Related issue number

Closes #33980

Checks

• [ ] I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• [ ] I've run scripts/format.sh to lint the changes in this PR.
• [ ] I've included any doc changes needed for https://docs.ray.io/en/master/.
  • [ ] I've added any new APIs to the API Reference. For example, if I added a method in Tune, I've added it in doc/source/tune/api/ under the corresponding .rst file.
• [ ] I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • [ ] Unit tests
  • [ ] Release tests
  • [ ] This PR is not tested :(