This migrates the above files from tempest. This includes tempest commits:
* interfaces_client.py: Idacc612bfed3d5a4abd58c8a987f68675b948f86
* test_interfaces_client.py: I976fd1d91dc3db4006f32b30e859981120487b0b
* interfaces.py: I64883306235dc3b90a3a878674532f77d825d5c4
to see the commit history for these files refer to the above Change-Ids
in the tempest repository.
Partially implements blueprint migrate-service-clients-to-tempest-lib
Change-Id: I758cf64ba1e6f760a60ed253cb9a8c9bc75ba73b