Add API config to node set

This moves API handling into the node object so now everything can be
done in one place.

TLS is required.
In the current form, auth must be setup by the caller.

hack/skaffold/virtual-kubelet/pod.yml

@@ -30,11 +30,4 @@ spec:
       valueFrom:
         fieldRef:
           fieldPath: status.podIP
-    ports:
-    - name: metrics
-      containerPort: 10255
-    readinessProbe:
-      httpGet:
-        path: /stats/summary
-        port: metrics
   serviceAccountName: virtual-kubelet