Implement runtime synchronization between source cookers.

[trgibeau]

We'll need a new optional interface for source data cookers that allows them to forward events, converted into a universal format. I was thinking something like IEventProducer, but we can decide more on that later.

We then need a type of composite cooker interface, IEventConsumer or similar, that can subscribe to the source data cooker to receive these events. The idea here is that this cooker will receive events from multiple even producers, coming from multiple sources (e.g. ETL & CTF).

The events coming from the event producer should be fed into a runtime component which will synchronize events from all input sources, and fed into the event consumer in time order.