💻 Removal idea: Quiz

[Felienne]

As with Parsons, it is not really well integrated into a trajectory and can be better done on paper. But, I could be swayed here if quizzes are used a lot, can you check @jpelay?

[boryanagoncharenko]

Users submit an answer for a quiz question 1470 times per day on average and complete quizzes 92 times per day on average. For comparison, users press the 'Run' button to execute a program 5650 times per day on average. Bear in mind that the difference between the quiz answer submissions and the quiz completions is normal because a quiz contains 10-ish questions. These estimates are based on the calls to /quiz/submit_answer, /quiz/review_quiz and /parse endpoints from log probes. Let me know if need further information.