Add user-selectable additional info fields

Besides generic info fields that apply to all puzzles, add the ability for users to add additional info fields when creating a listing that can contain other helpful pieces of info that don't apply to all categories of puzzles. Also, when creating a puzzle in a given category, allow the site to automatically add additional info fields when they apply to whole categories but not all puzzles (IE twisty puzzles have many interesting mathematical data points such as "God's Number", and the "Devil's Number" which specify the maximum number of moves from solved and the number of moves required to reach all states respectively). See for more suggestions: https://docs.google.com/document/d/1oBdwkw25perWuMIxyUHANJSo_Al13p0Xixj_qijgkNU/edit?tab=t.0