By Tobias Carroll Pizza is among the most versatile foods out there. Looking for a carefully-made pie with high-end ingredients? That’s absolutely possible. Looking for a dollar slice when you’re in the need for something cheap and filling? That, too, is something you’re likely to find without too much trouble in many cities. But what happens when pizza prompts an existential debate over its very nature? Well, then you’d have a sense of what’s taking place right now in Naples. In a new article for Air Mail, Elena Clavarino documents the heated rivalries that broke out when the owner of Crazy P…