Get rid of the split package in the gRPC extension artifacts

[mkouba]

Description

The package in question is the package io.quarkus.grpc and the artifacts are quarkus-grpc-stubs and quarkus-grpc.

Implementation ideas

No response

[quarkus-bot]

/cc @cescoffier, @michalszynkiewicz

[gsmet]

I think it should probably be put on the radar for 2.8. @cescoffier @michalszynkiewicz I don't know if you have a gRPC roadmap somewhere?

[cescoffier]

gRPC is part of the reactive roadmap. However we don't have this issue on it. We can definitely add it.

[mkouba]

FTR there's actually another package that needs to be fixed: io.quarkus.grpc.runtime.

I think that we should:

1. Extract the classes from the io.quarkus.grpc package into the quarkus-grpc-api artifact.
2. Rename the io.quarkus.grpc.runtime package in the quarkus-grpc-stubs artifact to io.quarkus.grpc.stubs. This change should not break anything because io.quarkus.grpc.runtime is not part of the API.