NEW YORK — A shooter unleashed a hail of bullets on Brooklyn’s famed Coney Island boardwalk early Sunday morning, wounding five people, one of them critically, police said. The attacker opened fire on a crowd standing near W. 20th Street on the Reigelmann Boardwalk about 2 a.m., police said. Police recovered 28 shell casings on the scene, a New York Police Department spokesman said. One victim, a 31-year-old man, is in critical condition at Coney Island Hospital, shot in the back. A second man, 19, went to the same hospital with a gunshot to his left leg. The other three victims went to NYU La…