As a user
I want to be able to collapse and expand all sections together
so I can see and hide the whole course, its resources and activities easily

Beside the course title in the course index there is a kebab menu with the options listed below:

• Collapse all: To collapse all sections from the course index in just one action.
• Expand all: To expand all sections from the course index in just one action.

(forget about 'Bulk edit' and 'Show labels' options for now)

Design

https://www.figma.com/file/OfCvqK069Oz6Fvqq2xcZWI/Create-a-course?node-id=1419%3A5795

Prototype:

• Mobile-view  : https://www.figma.com/proto/OfCvqK069Oz6Fvqq2xcZWI/Create-a-course?node-id=3285%3A38308&viewport=689%2C91%2C0.11091632395982742&scaling=scale-down&page-id=1419%3A5793&hide-ui=1

Acceptance criteria:

1. There is a new kebab menu beside the course title in the course index.
2. Users could collapse all section in the course index together in one action using 'Collapse all'
3. Users could expand all section in the course index together in one action using 'Expand all'
4. Expanding and collapsing actions are available both via mouse and keyboard.
5. When the section is collapsed, no activity will be shown.
6. When the section is expanded, all activities except those with no title into the section will be shown.
7. Collapsing and expanding sections won't affect section status in the course main content.