MonitorResource consumes too many resources

[wezell]

In a production environment, the MonitorResource should be as light weight as possible and consume too many resources.

We have a large production environment where the status checks performed by the MonitorResource are consuming up to 10% of the total app resources, specifically the DB check. The DB check runs an unbounded count on the contentlet table and that performs a full table scan in order to return the value. See image below from a production site that is using the /api/v1/system-status endpoint

[wezell]

PR: #18247

[dsilvam]

Passed Internal QA: Profiler not showing bottlenecks in the db check