SW-699: added documentation to RPCClientContextManagerMixin. renamed rpc_service.py module tp rpc.py, and it's classes to RPCClient and RPCService. Moved Request and ReplyMessage into rpc.py module. Mader MessageFactory and used it in FromBus and rpc.py

SW-699: major refactoring of the messagebus's BusListener and Service. Together with Jan-David and Auke, I decided to only allow a single API for the service, and we chose the most commenly used API based on the MessageHandlerInterface which we refactored into the ServiceMessageHandler. TODO: add docstrings, fix tests, adapt all Services in lofar python code.

SW-699: fixed some typos. Made TemporaryQueue bindable to and exchange. Route RPC-ReplyMessages via exchange to temporary reply queue

SW-699: major rewrite of FromBus/ToBus, AbstractBusListener and RPC/Service based on kombu/rabbitmq. This allows us to use a single lofar exchange (multiple exchanges are still allowed), and using auto-generated designated queues with subject based routin_keys.

SW-658: needed to refactor parts of the FromBus/ToBus because connections were not released. Took the opportunity to factor out common behaviour into abstract super class.

Task SW-516: Switch from qpid.messaging library to Apache Qpid Proton so we can use the message bus with Python 3

Task #8531: Modified Service to allow code-insertion at 4 new places. Currently tested with 'pass' in those function to assure backward compatiblity.