We use the cinder key for Nova by default, so a separate nova key is no
longer used.

Change-Id: I49ce6d36747e6c7d3a389d0afd2d034e8afdf8ed

We configure Cinder to use a 'backups' pool by default, but in CI we
create a 'backup' pool in Ceph. This change fixes CI to use 'backups'.

Change-Id: I53892137eb65ecc9530bd3859c651b12ab228a58

OVS upgrade jobs failed due to assigning an IP on the br-ex interface
(which is recycled during OVS upgrade). This change introduces a bridge
and veth pair for Neutron to use.

Change-Id: Ib3bee6e810fb8d31552d4c72c2a1ccae382c51f0

Background in [1].
Ubuntu uses pre 15.2.11 client and new 15.2.11 installs default that to false,
therefore not allowing Ubuntu clients to connect.

[1]: https://docs.ceph.com/en/latest/security/CVE-2021-20288/

Change-Id: Ic251b447026262eab4b406b8432cc009ca97ae82

Change-Id: I81a4f8f8b8faa7559740531bb16d8aec7fc23f9b

This makes it cleaner, allows reuse and outsourcing to zuul jobs
and enables us to create multiple of these overlay networks for
testing of more advanced scenarios.

Change-Id: Id557c81f68a7f34556854e7d6efc6eddfd2e7216