Add new versions of jQuery to the resource bundle

This PR adds jQuery 3, which is the latest jQuery version and it’s required by Bootstrap 4.

According to w3techs, jQuery 3.1.0, 3.1.1, 3.2.1 and 3.3.1 are the top 4 most used jQuery 3 versions.

core/files.js

@@ -265,5 +265,12 @@ var files = {
     },
 
     // Files [Staging]
-    'staging': {}
+    'staging': {
+
+        // jQuery
+        'resources/jquery/3.1.0/jquery.min.jsm': true,
+        'resources/jquery/3.1.1/jquery.min.jsm': true,
+        'resources/jquery/3.2.1/jquery.min.jsm': true,
+        'resources/jquery/3.3.1/jquery.min.jsm': true
+    }
 };