Deploy Ceph Bluestore with TripleO

Ceph Bluestore (https://ceph.com/community/new-luminous-bluestore) is alternative storage backend to filestore. Filestore has been the default Ceph storage backend for TripleO in both the documentation and in CI. This blueprint proposes to modify one of the TripleO CI scenarios with Ceph to use the bluestore backend and to document how to use the bluestore backend. Fortunately it seems to be possible to have TripleO deploy bluestore only by changing some parameters in TripleO Heat Templates.