feat: Add sidebar and library dropdown filter [FC-0114] (#2778)

* Add flow in course outline sidebar. Allows author to add new section/subsection/unit or any container from existing libraries via sidebar.
* Adds library dropdown filter and collections dropdown filter in add sidebar. Allows authors to filter containers by selected libraries and collections.

plugins/course-apps/proctoring/Settings.test.jsx

@@ -460,8 +460,9 @@ describe('ProctoredExamSettings', () => {
         screen.getByDisplayValue('mockproc');
       });
       // (1) for studio settings
-      // (2) for course details
-      expect(axiosMock.history.get.length).toBe(2);
+      // (2) waffle flags
+      // (3) for course details
+      expect(axiosMock.history.get.length).toBe(3);
       expect(axiosMock.history.get[0].url.includes('proctored_exam_settings')).toEqual(true);
     });