XD-1760 Rabbit/Redis Bus Short Circuiting

For colocated modules, when instructed by the lead admin,
hard wire the modules together.

- When binding a short-circuited producer, save his properties in
the binding so they can be used to revert, when the consumer is
unbound.

- When the consumer is unbound, bind the producer to the bus
(concurrently with the direct binding), remove the direct binding,
then stop the consumer (so there is always at least one subscriber
to the producing module's output channel.

- If the consumer is re-deployed, switch back to short circuit.

- TODO: Currently requires a producer property `shortCircuitAllowed`
Rabbit is fast - we have tests with no delay that always seem to work :smile: 

In this case, however, these null tests are really redundant because the test also verifies that the messages were actually delivered via the short circuit.