Epic 3: Implement context-aware sidebars

[jmakowski1123]

Parent ticket for tracking children:

• [x] https://github.com/openedx/frontend-app-course-authoring/issues/1045
• [x] https://github.com/openedx/frontend-app-course-authoring/issues/1189
• [x] https://github.com/openedx/frontend-app-course-authoring/issues/1190
• [x] https://github.com/openedx/frontend-app-course-authoring/issues/1195
• https://github.com/openedx/frontend-app-course-authoring/issues/1089 (handled in https://github.com/openedx/frontend-app-course-authoring/issues/1084)
• [x] https://github.com/openedx/frontend-app-course-authoring/issues/1200 Added:
• [x] https://github.com/openedx/frontend-app-course-authoring/issues/1221
• [x] https://github.com/openedx/frontend-app-course-authoring/issues/1270

[rpenido]

Some tasks changes:

Removed:

• https://github.com/openedx/frontend-app-course-authoring/issues/1089 (handled in https://github.com/openedx/frontend-app-course-authoring/issues/1084)

Added:

• https://github.com/openedx/frontend-app-course-authoring/issues/1221
• https://github.com/openedx/frontend-app-course-authoring/issues/1270

[bradenmacdonald]

Thanks @rpenido