NEW YORK — Three men were shot, one fatally, by a gunman who appeared to be firing an assault weapon outside a Queens catering hall early Sunday morning, police sources said. The violence started as an argument in a parking lot outside a banquet hall on Cross Bay Boulevard near Desarc Road in Ozone Park about 5 a.m., cops said. One man pulled out a long gun and opened fire, hitting a 38-year-old man in the chest, cops said. Medics took him to Jamaica Hospital but he couldn’t be saved. Surveillance video posted online shows the gunman firing rapidly with what appears to be an assault rifle. A 3…