If an operator wanted to configure something currently not available via
hieradata, they would only be able to do so for nova as it includes
::nova::config. This change addes the config classes for aodh, gnocchi,
keystone, neutron, swift, heat, ironic, mistral, and zaqar.
Change-Id: I3946e23cc5955d7c1a4dc4771d2708a6c8c2974b
Closes-Bug: #1793361
(cherry picked from commit 1a0714a864)