feat(stats): log events for ICE disconnected,reconnected and failed

When ICE disconnects, reconnects or fails the events will be logged
on both Callstats and "analytics".

JitsiConferenceEventManager.js

         JitsiConferenceEvents.CONNECTION_INTERRUPTED);
     chatRoom.addListener(XMPPEvents.CONNECTION_INTERRUPTED,
         function () {
-            Statistics.analytics.sendEvent('connection.interrupted');
+            Statistics.sendEventToAll('connection.interrupted');
         });
 
     this.chatRoomForwarder.forward(XMPPEvents.RECORDER_STATE_CHANGED,
 
     this.chatRoomForwarder.forward(XMPPEvents.CONNECTION_RESTORED,
         JitsiConferenceEvents.CONNECTION_RESTORED);
+    chatRoom.addListener(XMPPEvents.CONNECTION_RESTORED,
+        function () {
+            Statistics.sendEventToAll('connection.restored');
+        });
 
     this.chatRoomForwarder.forward(XMPPEvents.CONFERENCE_SETUP_FAILED,
         JitsiConferenceEvents.CONFERENCE_FAILED,

modules/statistics/statistics.js

 };
 
 /**
- * Notifies CallStats for ice connection failed
+ * Notifies CallStats and analytics(if present) for ice connection failed
  * @param {RTCPeerConnection} pc connection on which failure occured.
  */
 Statistics.prototype.sendIceConnectionFailedEvent = function (pc) {
     if(this.callstats)
         this.callstats.sendIceConnectionFailedEvent(pc, this.callstats);
+    Statistics.analytics.sendEvent('connection.ice_failed');
 };
 
 /**