Incorporate rest/grpc multiplexing and code gen for grpc protobuf & HTTP/2 use cases

[zeeshanlakhani]

Summary

Support tonic's implementation of gRPC, which is tied in with protobuf-codegen via prost.

Via a prompt, if grpc support is needed, which should run the server as a multiplex service, taking into account the grpc health check specifics, etc. Obviously, this addition should support tracing, etc. To implement the grpc-specific tracing needs, we can go ahead and gander here: davidB/tracing-opentelemetry-instrumentation-sdk#36. For the multiplexing, https://github.com/jvdwrf/axum-tonic/tree/main/src seems like a suitable lib already doing it.

Also, an example to look at: https://github.com/EmbarkStudios/server-framework.