Document recommended workflow

[hgeorgsch]

Typical workflow is

1. Design question list with ratings
2. Test without changing ratings. Cf. Test Quiz without Publication #235
3. Review and return to 1 until satisfied.
4. Run the quiz with students, updating ratings.
5. Reuse the quiz with updated ratings to a new course, and return to 1.

It is not obvious how we store transfer the instance in step 5, e.g. template, backup, or straight forward copy of the instance. It is not obvious that we want to keep templates, and we may end up with simplification here.

We should also note that step 5 should not copy user data. It may be tricky to use the backup interface because the designer has to tick which data to include and this is error-prone.