make loading screen tip presence configurable

customize.dist/application_config.js

@@ -13,6 +13,7 @@ define(function() {
      */
     config.notificationTimeout = 5000;
     config.disableUserlistNotifications = false;
+    config.hideLoadingScreenTips = false;
 
     config.enablePinning = true;
 

www/common/common-interface.js

@@ -430,7 +430,7 @@ define([
     UI.addLoadingScreen = function (config) {
         config = config || {};
         var loadingText = config.loadingText;
-        var hideTips = config.hideTips;
+        var hideTips = config.hideTips || AppConfig.hideLoadingScreenTips;
         var hideLogo = config.hideLogo;
         var $loading, $container;
         if ($('#' + LOADING).length) {