Enhance Application

• Fix refetching of data on different sites (either trough fetching parent or updating page with #key)
• Protect the course/unit_id route to not be able to go to any site.
• Fix roles in backend. A user should not be able to be enrolled to different courses as more than one role.
• Create unit modal. Validation and correct format of inputs. Could use svelte superforms.
• Removal of things. Add functionality for removing units, courses etc
• Redirecting on actions. Make redirects possible.
• App should not be a route, but a group.
• Enrolling of the user as lecturer in the created course.
• form validation
• Errors and errorhandling in Backend.