TT#2399 Switch from RRD page to grafana

* RRDs are gone for good, link statistics to grafana.
* Directly link into individual dashboards in new tab/window,
  since we don't iframe grafana (for now?)

Change-Id: Ica37ab5a9c9d50ed63142eb09e3b1de568c95aba

share/templates/widgets/admin_topmenu_settings.tt

@@ -19,7 +19,9 @@
         <b class="caret"></b>
     </a>
     <ul class="dropdown-menu">
-        <li><a href="[% c.uri_for('/statistics') %]">[% c.loc('System Statistics') %]</a></li>
+        <li><a href="/grafana/dashboard/file/system-statistics.json" class="ngcp-noback-link" target="_blank">[% c.loc('System Statistics') %]</a></li>
+        <li><a href="/grafana/dashboard/file/sip-statistics.json" class="ngcp-noback-link" target="_blank">[% c.loc('SIP Statistics') %]</a></li>
+        <li><a href="/grafana/dashboard/file/cluster-overview.json" class="ngcp-noback-link" target="_blank">[% c.loc('Cluster Overview') %]</a></li>
         [% IF c.config.features.callflow -%]
         <li><a href="[% c.uri_for('/callflow') %]">[% c.loc('SIP Call Flows') %]</a></li>
         [% END -%]