Implement secure RBAC for QoS API
Implement secure RBAC for QoS API

This commit updates the QoS policies 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: I62eb090cb42fad54e1baa8e282b41fe2fd471b0e

mahak/neutron,mahak/neutron,mahak/neutron,openstack/neutron,openstack/neutron,openstack/neutron