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 get the most attention is the documentary feature “Cantona,” getting a special screening in the official selection and, as the title suggests, all about him. Directed by David Tryhorn and Ben Nicholas, “Cantona” dives into the man behind the legend, the unquestionably gifted yet frequently unpredictable enfant terrible of French football, once branded unmanageable by the press.…