Remove rbac-policy callback into lib

Since most callback resources are located in neutron-lib,
rbac-policy still in [1], we can move it to the lib.

[1] https://github.com/openstack/neutron/blob/master/neutron/db/rbac_db_mixin.py#L31

Change-Id: Ib59703496bc8d13619358c39f5e01c00ee7211f4

neutron_lib/callbacks/resources.py

@@ -19,6 +19,7 @@ PORT = 'port'
 PORTS = 'ports'
 PORT_DEVICE = 'port_device'
 PROCESS = 'process'
+RBAC_POLICY = 'rbac-policy'
 ROUTER = 'router'
 ROUTER_GATEWAY = 'router_gateway'
 ROUTER_INTERFACE = 'router_interface'

releasenotes/notes/rehome-rbac-policy-callbacks-24fa12ad1ab4c443.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - The ``rbac-policy`` callback resource now available
+    as ``neutron_lib.callbacks.resources.RBAC_POLICY``.