ENG-6521: Add RabbitMQ export verifier to the genqa test app.

It assumes a running RabbitMQ server on kafka1. The verifier needs to be started
first. Then the server and the client.
Merge pull request #1497 from VoltDB/ENG-6521

ENG-6521: Add RabbitMQ export verifier to the genqa test app.

r=akhanzode