Course statistics selection limit removed, tooltip changes

Course statistics

• Limit removed: The feature had a limit of selecting maximum 40 courses. This was due to occasional crashing with courses that had many students. The limit is now removed, and a warning is added with a counter showing the amount of selected courses.
• Some optimizations were also made that will likely allow for more total students without failing, so the feature may now support more courses and students than it did before.
• The course search now does not de-select courses that have been selected but are not found after the search strings are changed

Tooltip improvements

• Student statistics page shows studyright activity status. The tooltip of this (the question mark icon in the column title) was changed to explain more clearly that it concerns current semester enrollments instead of enrolling to start studies in the programme.
• Studyprogramme overview > Studytrack and progress tab: Progress-table tooltip explains credit categories (for example, a student with 40 credits only belongs to category of 40-60, not in 20-40)

Internal

Backend was refactored. The following files or collections of files in backend/services folder are now given their own folders and separated in smaller files:

• Studyprogramme overview
• Populations (class statistics related functions)
• Course statistics