As a teacher
I want to be able to add a new activity in the course index
and see in which position I am creating it
so I can add resources and activities for learners
and set the activity up easier

This option will create a new activity just below the current element, whatever the current element is a section or an activity.

Prototype: https://www.figma.com/proto/OfCvqK069Oz6Fvqq2xcZWI/Create-a-course?node-id=3285%3A38308&scaling=scale-down

Acceptance criteria:

1. User needs permissions to add new activities.
2. The new activity will be created below the current activity for activities, and in the first position of the section for sections.
3. Activating the ‘Add a new activity’ option will show the Activity chooser as current behavior.
4. Choosing an activity type in the activity chooser will end in a new activity settings form.
5. While adding a new activity, a new ‘New xxx’ element will be shown in the course index to mark the location for the element, but it will not be saved till the user ‘Save changes’.

Technical tasks:

• Add the component to support create activity course state update