[user-guides] Add trove configuration overview
[user-guides] Add trove configuration overview

Change-Id: I32c38f1caa389275111021b61fab31e02205e96f
Closes-Bug: #1392419

AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals