Expose settings such as x-message-ttl on task queues

[muhrin]

Currently some quite important RMQ settings like x-message-ttl can't really be set from the outside i.e. when instantiating a communicator.

In general RabbitMQ has a lot of settings and many of them have defaults that aren't appropriate for certain applications. Therefore they should be configurable, however the constructors are getting quite parameter heavy and perhaps another mechanism such as a settings class would be more appropriate.