One person has been arrested and others are being sought after a New York City man was beaten and stabbed at the Showboat in Atlantic City on Wednesday night, authorities said. The attack took place around 9 p.m. in a public area of the Boardwalk hotel when several people got into an altercation with 25-year-old from the Bronx, according to Atlantic City police. The assailants punched and kicked the victim in addition to stabbing him. The New York man was hospitalized with injuries police said were not considered life-threatening. Police charged Marquise Cottman, 20, of Millville, with aggrava…