Sets the variable ``om_enable_rabbitmq_high_availability`` to ``true``
by default. An upgrade will therefore require some manual steps to
migrate from transient to durable queues. Note that this will be
caught by this precheck:
https://review.opendev.org/c/openstack/kolla-ansible/+/880274
Also updates the CI upgrade jobs to perform this migration. This will
need to be removed in Caracal.
Related-Bug: #2031294
Change-Id: I26a70d4722aaa4663eced5f5337840474c7b961c