Add 'Move to' option to the activity kebab menu

As a teacher
I want to be able to move an existing activity to another position in the same section
or to a different section
so I can order course content

This option will move the current activity to a different place in the same course.

Prototype: https://www.figma.com/proto/OfCvqK069Oz6Fvqq2xcZWI/Create-a-course?node-id=1503%3A2134&scaling=min-zoom

Acceptance criteria:

1. A modal should be shown for the user to choose the destination.

1. 1. User will see the whole structure of the course in the modal (similar to the course index)
   2. Selecting an activity or section will enable the ‘Move’ button.
   3. The activity’s new destination will be a position after the selected activity, or at the beginning of the selected section.
   4. All sections except the selected one (the source) will be collapsed.
   5. All labels will be shown in the modal. ‘(Untitled)’ will be shown for labels with empty title.
2. Once the action is finished:
   1. The user stays in the same ‘source’ position.
   2. A toast notification will be shown once the action has been completed.
3. The visibility of an activity could change when moving to a different section based on the visibility of the source and destination sections.
   1. Moving from visible to hidden section: 'Show on course page' -> 'Available but not shown on course page'
   2. Moving form hidden to visible section: 'Available but not shown on course page' -> 'Show on course page'

Technical tasks:

• "Move to" and "Copy to" modal component
• Add cm_move state actions