Write script to convert json cards into spreadsheet

[barney-walker]

• Info about each card in stored as a json object to make it easy to do version control. See Add Cards #10 .
• We need cards in a spreadsheet to populate design templates. See https://docs.google.com/spreadsheets/d/1fajcgzR4e4WbyHAVDwzwkcgNXaTW95ivhbjnq8TGqj0/edit#gid=182220874