event_rabbitmq: replace exchange with routing_key

Closes #220

(cherry picked from commit eb233f894b1364d20e1f3461304d79a077102a3a)

Conflicts:
	modules/event_rabbitmq/event_rabbitmq.c

(cherry picked from commit 5ea61c0e085dd4398717d1810773ef89446470dd)

Conflicts:
	modules/event_rabbitmq/event_rabbitmq.c