The busiest actor in Cannes this year is a man considerably more famous for his artistry on the football field than on screen. Eric Cantona has an impressive three films in the festival, with the French soccer legend and Manchester United hero acting in two and the subject of another. In Avril Besson’s debut feature “Marvellous Mornings,” he plays a wine merchant alongside India Hair and Raya Martigny. Then there’s Ali Cherri’s short “The Sentinel,” premiering in Critics’ Week. But likely to