Squash migrations

...t/quiz/migrations/0001_refactor_sport_and_add_criteria.py

unisportomat/quiz/migrations/0002_wissensnack_text.py

unisportomat/quiz/migrations/0003_auto_20210517_1437.py

unisportomat/quiz/migrations/0004_criterion.py

unisportomat/quiz/migrations/0005_auto_20210517_1520.py

...s/0006_rename_criterion_ratings_sport_criteria_ratings.py

unisportomat/quiz/migrations/0007_auto_20210518_1521.py

unisportomat/quiz/migrations/0008_alter_sport_url.py