Standardize on method for adding more alternatives in question

Today we have different methods for adding more alternatives to the question types this implies for:

1. Multiple choice: one admin page (/admin/quiz/multichoice) where you can set "Maximum number of alternatives allowed: x", and one when adding a question (/node/add/multichoice/) where you have a button for "add more alternatives" which adds one more alternative with ajax when clicked. This also have a non-js fallback (allthough with a small bug: #629674: MCQ without js loses alternatives marked correct when adding more questions )
2. Matching: one admin page (/admin/quiz/matching) where you can set "Match Question Size: x"
3. Scale: one admin page (/admin/quiz/scale) where you can set "Maximum number of alternatives allowed: x"

I feel this is functionality that belongs to the question creator, not the quiz administrator, and thus that we should move this from the admin pages to the node/add pages, so that #1 (button to add more alternatives to a question) is the right way to do this. For MCQ and Matching we could display 2 or 3 alternatives and a button, for Scale 6 (?) alternatives and a button.

It might not be something we need to prioritize right now, but eventually Quiz should do this in a consistent way, and hand this control over from the admin to the content creator.