Adds support for Keystone V3 API

Updated trove client to support Keystone V3 API. The
Keystoneclient session object is used for authentication, retrieving
the service catalog and HTTP connection/session management.

Added additional CLI parameters for Keystone V3.

Change-Id: I800c252234be2ff11d818cf7513c61c5431eb15c
Closes-Bug: 1323866