As it's recommended to have an independent RabbitMQ cluster for Trove
Guestagent, we need to make it possible to easily use also different
user/password set for it.
It's also important to control quorum queues independently, as migration
between quorum queues and classic queues for guestagent cluster
is quite cumbersome and potentially should be avoided as might
bring severe disturbances.
Change-Id: Ib68778a8cb8535d7400be04f02d332ba0344d20e