Merge PR #66482 into tentacle

* refs/pull/66482/head:
	mgr/prometheus/test_module: Adding unit-test for new classes
	mgr/prometheus: metrics header for standby module
	mgr/prometheus: Use RLock to fix deadlock in HealthHistory
	mgr/TTLCache: fix PyObject* lifetime management and cleanup logic
	mgr/prometheus: prune stale health checks, compress output

Reviewed-by: Patrick Donnelly <pdonnell@ibm.com>
Reviewed-by: Radoslaw Zarzynski <rzarzyns@redhat.com>