This patch add the service "radosgw.usage" to collectors
in order to allow rating on ceph object storage usage per project.
The service unit is set to GB.
The following work has been done:
- Add radosgw.usage transformer for ceilometer
- Add radosgw.usage collect function to ceilometer and gnocchi (new
and deprecated format)
- update doc
Change-Id: Ia49c76a285950475ed0a9f15d35b2f23b11e5ef3
e605827a15