Use an event to eliminate latency on job queuing

[arkanes]

The current implementation of FetchNextJob creates a 15 second latency between the startup of the server and the processing of the first event, since everything is running in-process with MemoryStorageProvider we can use an event awaken FetchNextJob and eliminate the latency.

This is the simplest implementation of this solution, FetchNextJob could probably be re-written to eliminate the polling entirely.

[DaniilSokolyuk]

why not merge? 15 second is so big latency