rgw multisite: enable more than 1 realm per cluster

rgw multisite: enable more than 1 realm per cluster

Make it so that more than one realm, zonegroup,
or zone can be created during a run of the rgw
multisite ansible playbooks.

The rgw hosts now need to be grouped into zones
and realms in the inventory.

.yml files need to be created in group_vars
for the realms and zones. Sample yaml files
are available.

Also remove multsite destroy playbook
and add --cluster before radosgw-admin commands

remove manually added rgw_zone_endpoints var
and have ceph-ansible automatically add the
correct endpoints of all the rgws in a rgw_zone
from the information provided in that rgws hostvars.

Signed-off-by: Ali Maredia <amaredia@redhat.com>
(cherry picked from commit 71f55bd54d923f610e451e11828378c14f1ec1cc)