Configure x-request-id support in the default ootb examples

[smarterclayton]

We should configure x-request-id correctly for our out of the box examples, and ensure that gateways can easily then integrate their own request tracing.

For vLLM, it would be very desirable to ensure that x-request-id is sufficiently scoped in logs such that we can identify request start, request end, and any related requests (i.e. POST /v1/completions or similar should show the request id)