Initial stab at monitoring_check::cluster

initial stab at cluster check, just need to know if i'm going in right direction?
I do not want to differ from mainline any more than we already have.

The locking functionality is more nuanced than this.

In order to get sane results, the check really should see if there is already are result for the minute it is running in (assuming it runs every minute)

Otherwise, even with the lock, we will still get more events-per-minute than we really want.