Revert "Refactor index.js to use new export/import API for apps"

This reverts commit 65952f81.

aleksis/apps/alsijil/assets/index.js

-export default [
-    { path: "/coursebook/:lessonId", component: () => import("./components/coursebook/CourseBook.vue"), props: true },
-];
+import CourseBook from './components/coursebook/CourseBook.vue'
+import messages from "./messages.json";
+
+window.router.addRoute({ path: "/app/alsijil/coursebook/:lessonId", component: CourseBook, props: true });
+
+window.i18n.registerLocale(messages);