Support @Inject-ing clients without @CXFClient at least in unambiguous cases.

[ppalaga]

Follows up #952 (comment)

Pure @Inject at least for the non-ambiguous cases sounds interesting though. [...] If the case is ambiguous, the extension should throw an exception (ideally at build time) advising the user to use @CXFClient. Contributions are welcome!

[amoscatelli]

I think this will lead to ambiguity problems between injecting the service impl and the SEI Proxy client.
To tell the truth, I still can't understand what's the sense in injecting the service impl.

I hope I am wrong.

[ppalaga]

That's a good point. If a user annotates his implementation class with @ApplicationScoped or similar, he may expect it to be passed to injection points having the SEI type. That would conflict with the client proxy also implementing the SEI. I wonder whether that conflict would not exist already with the present implementation. I guess a CDI Qualifier could be used to keep the two candidate beans apart. I need to try how it works with our current implementation.