create messaging queue

[vlopes11]

Currently, the co-processor client relies on its internal storage and a convoluted sequence of timeouts in order to compute and fetch proofs.

There must be a message layer that will be assigned to a proof task to be forwarded to the prover workers, and will allow for the client to subscribe to a channel and wait for his proof.

One ideal option is RabbitMQ as other solutions such as Kafka are scoped for different contexts such as streaming.