feat(full): Implementing download unit report for frontend

Adds a way to download and generate report trough the frontend.

How to test:

• Create a course
• Create units
• CLick on the buttons

Note:

• There are implemented to give user notification when its done generating

Based on: !35 (merged) !43 (merged) !42 (merged)

Closes #55 (closed) #39 (closed)

Co-authored-by: @ulrikyi