Add RabbitMQ support, so we can offload tiresome tasks

[petterroea]

This PR introduces:

• A service architecture-type solution for providing access to external systems that may change over time
• A RabbitMQ connection thread using Pika
• Fixes to how the server is ran such that it works with worker threads
  • Running gunicorn with pserve caused the server to fork into workers after init, leaving the connection thread behind.