Introduce JobResultStore

This issue includes introducing the interface and coming up with a in-memory implementation of it that should be integrated into the Dispatcher.

• We’ll introduce the new interface JobResultStore
• We’ll remove the RunningJobsRegistry a replace its functionality with (Standalone|Embedded)JobResultStore (This is basically only about RunningJobsRegistry#setJobFinished method
• The JobResultStore should be initialized along the JobGraphWriter since both components are closely related.