EigenFlow Kafka Publisher should use a single topic per message type

[WadeWaldron]

The EigenFlow platform currently publishes to a separate topic per job. This means consumers need to know what jobs exist in advance which is not ideal.

Instead it could publish to a single topic per event type (RunEvent, StageEvent, MetricsEvent). The events would then include the Job Id. This would mean consumers would not need to be aware of the different job types in advance.