NEW YORK — The beating of drums. The bleating of horns. And now: the buzz of police drones. New York City’s Labor Day revelry will have a new noise this year, as the police department plans to deploy the remote-controlled, camera-equipped aircraft to monitor large gatherings — even backyard parties — connected to West Indian American Day celebrations in Brooklyn. The plan was announced at a briefing Thursday in Brooklyn before J’ouvert and the West Indian American Day Parade, events that honor t