Configuration to disable auto-declare queues in worker

We found that in our use case — binding to hundreds or thousands of queues at startup, all of which have already been declared by the publisher or by other setup code — this speeds up worker startup time considerably by avoiding thousands of unnecessary round trips to call the AMQP `queue.declare` method.

Does this look good to you?  Any advice or suggestions are welcome, this has only been lightly tested so far.