Add labels panel to nodepool dashboard

Expose more data into our nodepool grafana dashboard showing the break
down of which images (labels) are being build / ready / inuse / delete
state.

This can be helpfully to see the type of nodes we are running.

Change-Id: I30929c2b478d6a67111d1b52d1b4103434b43732
Signed-off-by: Paul Belanger <pabelanger@redhat.com>

grafana/nodepool.yaml

@@ -74,6 +74,30 @@ dashboard:
           targets:
             - target: aliasByNode(stats.gauges.nodepool.manager.*.nodes.delete, 4)
           type: graph
+    - title: Nodepool Images
+      showTitle: true
+      height: 320px
+      panels:
+        - title: Building Nodes
+          span: 3
+          targets:
+            - target: aliasByNode(stats.gauges.nodepool.label.*.nodes.building, 4)
+          type: graph
+        - title: Ready Nodes
+          span: 3
+          targets:
+            - target: aliasByNode(stats.gauges.nodepool.label.*.nodes.ready, 4)
+          type: graph
+        - title: Used Nodes
+          span: 3
+          targets:
+            - target: aliasByNode(stats.gauges.nodepool.label.*.nodes.used, 4)
+          type: graph
+        - title: Deleting Nodes
+          span: 3
+          targets:
+            - target: aliasByNode(stats.gauges.nodepool.label.*.nodes.delete, 4)
+          type: graph
     - title: Job Runtimes
       showTitle: true
       height: 250px