Question pools that vary together #69
Description
Currently, question pools in quizzes allow you to group a bunch of questions together, and one will be selected to be shown to the quiz taker. However, each pool is independent. This is a problem for asking students things that span multiple questions; e.g., showing them a code block in one question and then another question that subsequently asks follow-up questions. In those cases, there needs to be a way to mark a set of question pools as "varying together", based on the seed. Not every pool will need this behavior, and a single quiz might have multiple sets of pools that need to vary together. This will require adding a new field to the pools, and also some new logic to the pool selection process.
This is all handled through the quizzer in the frontend.