rsockets: Support native IB addressing on connected rsockets

rsockets: Support native IB addressing on connected rsockets

Update rsockets to support AF_IB addresses on connected rsockets.
Support for datagram rsockets is more difficult as a result of
using real UDP sockets for QP resolution, so that support is
deferred.  For connected sockets, we need to update internal
checks to handle AF_IB.

Allow the user to specify GID addresses into the rsocket sample
applications.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>