Clean up Labels and Annotations

[manno]

• Annotation fleet.cattle.io/managed appears unused, label of the same name is in use
• Label fleet.cattle.io/bootstrap-token is unused
• Annotations fleet.cattle.io/cluster, fleet.cattle.io/cluster-namespace are never used on a Cluster resource

[manno]

https://fleet.rancher.io/next/ref-configuration#labels

[thardeck]

As described in the documentation mentioned above the annotations fleet.cattle.io/cluster and fleet.cattle.io/cluster-namespace are used on a cluster namespace to reference the cluster registration namespace and to check if the namespace can be cleaned up.
The code reflects the documentation so the two annotations need to stay.

e.g.:

fleet/pkg/controllers/cluster/controller.go

Lines 94 to 95 in c1f52da

	clusterNS := ns.Annotations[fleet.ClusterNamespaceAnnotation]
	clusterName := ns.Annotations[fleet.ClusterAnnotation]