probe: merge controls from different probes

This change creates a host topology from cluster-wide probe using
kubernetes nodes with cordon/un-cordon control. This also adds the
logic to merge the controls coming from different probes for host
topology.

examples/k8s/cluster-role.yaml

@@ -15,7 +15,6 @@ rules:
   - pods/log
   - replicationcontrollers
   - services
-  - nodes
   - namespaces
   - persistentvolumes
   - persistentvolumeclaims
@@ -23,10 +22,6 @@ rules:
   - get
   - list
   - watch
-  - create
-  - update
-  - patch
-  - delete
 - apiGroups:
   - ""
   resources:
@@ -99,3 +94,13 @@ rules:
   verbs:
   - list
   - watch
+- apiGroups:
+  - ""
+  resources:
+  - nodes
+  verbs:
+  - get
+  - list
+  - watch
+  - update
+  - patch