Better Polls

Several suggestions:

1. Allow multi-question surveys.

2. allow more than 5 answers per question

3. allow selecting multiple answers (which is suggested already e.g. here: https://heartbeat.canny.io/feature-requests/p/multiple-choices-on-polls)

These are my suggestions for threads. For courses, the following would be good in addition to above features:

4. add a question type with text answer

5. add a question type with numeric answer, e.g. 0-10.