Implement Ceph backend for Glance / Cinder / Nova

The new lib installs a full Ceph cluster. It can be managed
by the service init scripts. Ceph can also be installed in
standalone without any other components.
This implementation adds the auto-configuration for
the following services with Ceph:

* Glance
* Cinder
* Cinder backup

Change-Id: Ifec850ba8e1e5263234ef428669150c76cfdb6ad
Implements: blueprint implement-ceph-backend
Merge commit 'refs/changes/13/65113/14' of https://review.openstack.org/openstack-dev/devstack