Octavia is missing oslo_messaging_rabbit settings

Detailed Description

Octavia defaults.cue templates are missing the following properties:

rabbit_transient_quorum_queue: *true | bool
use_queue_manager:             *true | bool
rabbit_stream_fanout:          *true | bool
rabbit_qos_prefetch_count:     *250 | int

This is also problematic for RabbitMQ upgrades, because the rabbit_transient_quorum_queue: false will cause non durable non exclusive queues to be created which are a deprecated feature. This will cause the rabbitmq-diagnostics check_if_any_deprecated_features_are_used check inside the upgrade-pre job to fail during the upgrade from 4.1 to 4.2.

https://www.rabbitmq.com/release-information/deprecated-features-list

We also need to provide this patch inside the octavia image so the migration works in existing clusters.

We should also figure out why the error during the upgrade was not caught by the integration test.

Specification

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this issue are to be interpreted in the spirit of RFC 2119, even though we're not technically doing protocol design.