Adding readiness check for grafana

Adding readiness check to not create additional scripts
during dashboards import.
Also remove useless liveness check.

Change-Id: I929378ce4154c972c836fd33d4871740f334fcfc

service/grafana.yaml

@@ -7,10 +7,10 @@ service:
     - name: grafana
       image: grafana
       probes:
-        readiness: "true"
-        liveness:
-          command: "true"
-          type: "exec"
+        readiness:
+          type: "httpGet"
+          port: {{ grafana.port.cont }}
+          path: "/"
       daemon:
         command: /usr/sbin/grafana-server --homepath=/usr/share/grafana --config=/etc/grafana/grafana.ini
                  cfg:default.paths.data=/var/lib/grafana