Update documentation to include usage for new projects
Update documentation to include usage for new projects

The oslo.policy bits to generate documentation and use the oslo.policy
CLI scripts is usually copy/pasted from other services that have
already done that work. This commit attempts to pull that information
into the usage section of oslo.policy, complete with examples, instead
of making OpenStack developers hunt through projects to find examples
they can use. Or wonder why or how this tooling works.

Change-Id: Ie74888b09bb836c192a88c5beddd86297c8bceda
Closes-Bug: 1766953

openstack/oslo.policy