Support OPA for RabbitMQ

A large percentage (40%) of communication within our network happens over RabbitMQ. Number of microservices have been created which can consume messages from the queue. The challenge we're facing is controlling which microservices are allowed to consume the messages. An attempt was made through OPA plugin, however this did not work.

Primary impact of not being able to do this is:

• define the permissions logic outside of OPA

• convert RabbitMQ to operate of HTTP

Ask is to add support for RabbitMQ to OPA plugin.