#22603 Use exchange instead of queue for replies in rabbitmq connector

Use exchange instead of temp-queue in rabbitmq plugin. This allows MCollective to work across federated servers as federation only mirrors exchanges, not queues. For backward-compatibility it is disabled by default, to enable:

    plugin.rabbitmq.use_reply_exchange = true

servers *should* work no matter if it is turned on or off on client (as server just uses 'reply-to' path)