This migrates the above files from tempest. This includes tempest commits:
* tenant_networks_client.py : Ie0f6e709cbb3a215752344cb39f2f7a6f5a7a91b
* tenant_networks.py : Ica929c402a3d042ae751302384e68853eb28b405
* test_tenant_networks_client.py: I3ad6761651cec5e66012d08e6b63322f53286a5c
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: Ie98ff37137e25e73eb77acb0b5b7e53184842540