This module contains some constants and helper functions
which may be used in neutron, neutron staduim and neutron
3rd party projects.
Also already existing module _policy with policy engine
implementation for internal use of neutron-lib for moved to
the new neutron_lib.policy module and is now named
neutron_lib.policy._engine
Partially Implements: blueprint neutron-policy-in-code
Change-Id: Ie581788f78f6d83ae470981830df9e90a7cb72e8
59c60b68fb