This migrates the above files from tempest. This includes tempest commits:
* hosts_client.py: Ife5bdbbcbdd856ecbce66e8b9c74c70dbb93f077
* test_hosts_client.py: Ifc4aa410d1db84ea8c43c64d1feadd74dbfbc4a4
* hosts.py: Ica929c402a3d042ae751302384e68853eb28b405
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: I59c82bc896d5036d936e6f9cddb3c7b004648dde