Add tests for project users interacting with roles
Add tests for project users interacting with roles

This commit introduces test coverage that explicitly shows how
project users are expected to behave global role resources. A
subsequent patch will clean up the now obsolete policies in the
policy.v3cloudsample.json policy file.

Change-Id: Id0dc3022ab294e73aeaa87e130bea4809f8c982b
Partial-Bug: 1806713

openstack/keystone,mahak/keystone,mahak/keystone,openstack/keystone,openstack/keystone,mahak/keystone