Implement secure RBAC for zones
Implement secure RBAC for zones

This commit updates the policies for zones to understand scope
checking and account for a read-only role. This is part of a broader
series of changes across OpenStack to provide a consistent RBAC
experience and improve security.

Change-Id: Ib31cb82cbf62460723f261f1eaeec918633508c0

openstack/designate,openstack/designate,openstack/designate