Backport Microprofile Client to 3.1.x branch

[Roberto Cortez]

Hi,
I was wondering if it would be ok to backport the Microprofile Client module 
from the master branch in the 3.1.x branch.
This is because the latest spec of Microprofile, version 1.3, targets JAX-RS 
2.0 and requires the Rest Client 1.0, implemented in 3.2.x, which is JAX-RS 2.1.
If this is ok, I wouldn't mind submitting a PR myself with the port.
Cheers,Roberto