The original cluster registration operator assumed the RegisteredCluster CRs were on the cluster on which the controller was deployed. We need to update the RegisteredCluster controller to be KCP-aware. The KCP credentials can be provided in a k8s secret at least initially, as we don't know yet entirely what KCP sharding will look like and whether we'll have each controller instance watching multiple shards or just one.

The controller should watch for RegisteredClusters across KCP. You'll need to follow the mechanics described here to install the RegisteredCluster API in KCP.