Implement secure RBAC for quota classes
Implement secure RBAC for quota classes

This commit updates the policies for quota classes 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: I5c8ebcf72ab158021deab772693b869c35962a2b

openstack/manila,openstack/manila