Convert rule API to RPC

rule_model.py

To support the new distributed architecture, all of the API models must operate via RPC calls on the message bus. At the very least this requires modifying the current models so they utilize the RPC abstraction (even if it's faked) to communicate with the other nodes on the message bus. Ideally this code would actually send RPC messages via deepsix until the new distributed architecture is in place. This would ensure that all the serialization and message handling is done properly. We have a separate blueprint for each model so that we can track who is working on what.