Refactor how we validate zip file contents
Refactor how we validate zip file contents

This is preparation for adding the ability to see if the zip file looks like an ArcGIS file.

robinwhittleton/whitehall,YOTOV-LIMITED/whitehall,hotvulcan/whitehall,ggoral/whitehall,askl56/whitehall,alphagov/whitehall,ggoral/whitehall,askl56/whitehall,hotvulcan/whitehall,alphagov/whitehall,YOTOV-LIMITED/whitehall,alphagov/whitehall,hotvulcan/whitehall,askl56/whitehall,robinwhittleton/whitehall,hotvulcan/whitehall,YOTOV-LIMITED/whitehall,askl56/whitehall,robinwhittleton/whitehall,alphagov/whitehall,robinwhittleton/whitehall,ggoral/whitehall,ggoral/whitehall,YOTOV-LIMITED/whitehall