Document keystone role element in container ACL
Document keystone role element in container ACL

The use of a keystone role name in container ACLs is supported
and tested. This patch adds documentation.

[1] https://github.com/openstack/swift/blob/fb3d01a974fb7df8cfadc56ff15bdc04b3c90759/swift/common/middleware/keystoneauth.py#L491-L497
[2] test.unit.common.middleware.test_keystoneauth.TestAuthorize.test_authorize_succeeds_for_user_role_in_roles

Change-Id: I77df27393a10f1d8c5a43161fdd4eb08be632566
Closes-Bug: #1705300

nadeemsyed/swift,smerritt/swift,nadeemsyed/swift,smerritt/swift,matthewoliver/swift,tipabu/swift,swiftstack/swift,smerritt/swift,matthewoliver/swift,openstack/swift,openstack/swift,smerritt/swift,tipabu/swift,matthewoliver/swift,openstack/swift,tipabu/swift,swiftstack/swift,swiftstack/swift,nadeemsyed/swift,matthewoliver/swift,tipabu/swift,nadeemsyed/swift,openstack/swift