1. Port QoS clients from neutron qos and compliys with
tempest network service client format.
2. Port QoS API tests from neutron qos to be part of
vmware_nsx_tempest test suites.
3. Both NSX-v and NSX-t support QoS.
Change-Id: I20c90229a733b1b3a9ec4a623493298ec96c663b