Today the clusterversion controller Watch()es ClusterDeployment, but that's it. So it'll refresh our labels if the CD changes, or on the default occasions controller-runtime decides (which I think may be a) when the controller restarts, and b) every 1000s?)

Add a tunable that triggers a reconcile on an interval settable from HiveConfig

We could do this the same way we do the one on the machinepool controller – but that may enqueue all ClusterDeployments at once. It might be better to use the method suggested in HIVE-2542 where we requeue each individual CD with RequeueAfter(interval + jitter) to avoid bunching.