As we're targeting campus HA for non ceph backends we need a default recommended option for Glance

The default choice is to rely on cinder for glance which is already fully supported but not tested in a multistore context. Each site that includes storage will have a store configured to use the local-to-site cinder backend.

This epic tracks the possible glance operator work required to configure glance multistores backed by cinder as well as the necessary testing. 

This epic should also confirm the campus HA Glance design for third party backends.