Update Role and setting descriptions (Ceph & Cinder)

Added more useful descriptions for
* Cinder role (Bug 1260881)
* Ceph role (Bug 1260882)
* Ceph Storage settings

Change-Id: I21ceba77a9c329be70410c9b4445478b459b77cd
Closes-bug: #1260881
Closes-bug: #1260882
Merge "Update Role and setting descriptions (Ceph & Cinder)"