Move iframe-render script earlier to run it as fast as possible

Author: Vladyslav Tymofeiev

lms/templates/main.html

@@ -48,6 +48,8 @@
       </title>
   </%block>
 
+  <script async type="text/javascript" src="${static.url("lms/js/iframe-render.js")}"></script>
+
   % if not allow_iframing:
       <script type="text/javascript">
         /* immediately break out of an iframe if coming from the marketing website */
@@ -126,7 +128,6 @@
     }).call(this, require || RequireJS.require);
   </script>
   <script type="text/javascript" src="${static.url("lms/js/require-config.js")}"></script>
-  <script type="text/javascript" src="${static.url("lms/js/iframe-render.js")}"></script>
   <%block name="js_overrides">
     ${render_require_js_path_overrides(settings.REQUIRE_JS_PATH_OVERRIDES) | n, decode.utf8}
   </%block>