Discuss switching from Configmaps to store users overrides to ARCs, for both Platform and User monitoring stack.

This mean creating ARCs also in the `openshift-user-workload-monitoring` namespace  , even though CMO doesn't watch this namespace for ARCs today, so initially these would only be read by the monitoring-plugin API for the UI.

All other alert will persist the mapping in the rules themselfs when possible or be mapped by the matcher.go script.