refactor: move xmodule folder to root

- Moving xmodule folder to root as we're dissolving sub-projects of common folder in edx-platform
    - More info: https://openedx.atlassian.net/browse/BOM-2579
- -e common/lib/xmodule has been removed from the requirements as xmodule has itself become the part of edx-platform and not being installed through requirements
- The test files common/lib/xmodule/test_files/ have been removed as they are not being used anymore

xmodule/assets/vertical/public/js/vertical_student_view.js

@@ -0,0 +1,28 @@
+/* JavaScript for Vertical Student View. */
+
+/* global Set:false */ // false means do not assign to Set
+
+// The vertical marks blocks complete if they are completable by viewing.  The
+// global variable SEEN_COMPLETABLES tracks blocks between separate loads of
+// the same vertical (when a learner goes from one tab to the next, and then
+// navigates back within a given sequential) to protect against duplicate calls
+// to the server.
+
+import BookmarkButton from 'course_bookmarks/js/views/bookmark_button';
+import {markBlocksCompletedOnViewIfNeeded} from '../../../../../lms/static/completion/js/CompletionOnViewService.js';
+
+var SEEN_COMPLETABLES = new Set();
+
+window.VerticalStudentView = function(runtime, element) {
+    'use strict';
+    var $element = $(element);
+    var $bookmarkButtonElement = $element.find('.bookmark-button');
+    markBlocksCompletedOnViewIfNeeded(runtime, element);
+    return new BookmarkButton({
+        el: $bookmarkButtonElement,
+        bookmarkId: $bookmarkButtonElement.data('bookmarkId'),
+        usageId: $element.data('usageId'),
+        bookmarked: $element.parent('#seq_content').data('bookmarked'),
+        apiUrl: $bookmarkButtonElement.data('bookmarksApiUrl')
+    });
+};