Consider merging the dispatcher communication responsibility of EE into scheduler

[jonathan-eq]

There is now a lot of cross component communication between scheduler and EE as the responsibility of communicating with the running job is split between them. This should be refactored so the responsibility is contained in one component, and we won't have to forward events back and forth through separate queues between EE and scheduler.

I think moving the zmq router from EE into scheduler would be a good idea, so all events will be collected in scheduler; and we can forward them to EE for merging into the snapshot and emitting the changes to GUI.