Implement secure RBAC for share types
Implement secure RBAC for share types

This commit updates the policies for share types 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: Id96bb3c7295dd2eae58a168fd5a265825c040a29

openstack/manila,openstack/manila