ClusterResourceQuota controller: Expose metrics about resource discovery

The current implementation of the [CRQ controller](https://github.com/openshift/cluster-policy-controller/blob/f1fe7bf5a097fb85a05d6ed61f4eedea9e71077b/pkg/quota/clusterquotareconciliation/reconciliation_controller.go#L165) does not sufficiently reports whether discovered resources are empty or whether the CRQ controller is reconciling properly. For that, we need metrics that will reflect whether:

• resource discovery returns valid data (e.g. returning empty list of resources with empty error is sign of something incorrect happening)
• CRQ controller is properly reconciling all CRQ objects. E.g. every object is expected to be forcefully updated every 5 minutes by default. Metrics might report the last time any CRQ object was successfully updated.
• other indication of correct/incorrect behavior

This will require analysis of the code to detect the right spots for recording. The KCM operator might be extended to report whether the CRQ controller degraded or not manifesting suspicious activity.