This creates two archive policies "ceilometer-low" and
"ceilometer-low-rate" in Gnocchi. And use them to create metrics
in Gnocchi.
The archive policies settings can now be configured in
gnocchi_resources.yaml.
This requires upcoming release of coming
(https://github.com/gnocchixyz/gnocchi/pull/655)
Change-Id: Ib804ef4652af9d40338ad970690f6e92f12ed636