fix #248: crossorigin attribute is needed when including with type="module"

For more info, see:
 * https://html.spec.whatwg.org/multipage/urls-and-fetching.html#cors-settings-attributes
 * https://jakearchibald.com/2017/es-modules-in-browsers

Author: nicoulaj

src/views/index.ejs

@@ -236,7 +236,7 @@
 
     <link href="/stylesheets/style.css" rel="stylesheet">
 
-    <script src="/javascripts/services/bootstrap.js" type="module"></script>
+    <script src="/javascripts/services/bootstrap.js" crossorigin type="module"></script>
 
     <link rel="stylesheet" type="text/css" href="/libraries/jam/css/jam.min.css">
 
@@ -250,4 +250,4 @@
       <%= appCss %>
     </style>
   </body>
-</html>
+</html>

src/views/setup.ejs

@@ -129,6 +129,6 @@
 
 <script src="/libraries/knockout.min.js"></script>
 
-<script src="/javascripts/setup.js" type="module"></script>
+<script src="/javascripts/setup.js" crossorigin type="module"></script>
 </body>
-</html>
+</html>