22603 - add rabbitmq.use_reply_exchange

RabbitMQ's federation mirrors only exchanges, so any reply to client
has to be send using direct exchange instead of (temp-)queue.

Adds rabbitmq.use_reply_exchange option that enables new reply behaviour.
Add tests for rabbitmq.use_reply_exchange

This patch also relays the make_target tests as I found the previous
version too dense to easily update.
Merge pull request #124 from richardc/rabbitmq_federation

22603 add rabbitmq.use_reply_exchange to support rabbitmq federation