Refactored long methods in file views.py in users folder and serializers.py in workouts folder.
Parts of the code in the methods are extracted to new methods.

Comments removed from code.

When viewing high scores for a specific exercise, it is now also
possible to rank the high score list by total units performed.

- The high score list is now rendered as a table
- For exercises a new column showing units performed is visble
- For workouts only the score column is visible
- The high score list is sorted by both score and units in the backend