Add creates a new metrics Calculator and adds it to the Manager.

Calculator runs in a goroutine and periodically calculates and publishes Prometheus metrics which will be exposed at our /metrics endpoint.

ReconcileObserver is used to track, log, and report metrics for controller reconcile time and outcome.

ReconcileOutcome is used in controller "reconcile complete" log entries, and the metricControllerReconcileTime above for controllers where we would like to monitor performance for different types of Reconcile outcomes.