Demolition has officially started on the vacant stores at the Monmouth Mall as one of the state’s largest shopping destinations begins its transformation into an open-air town center called “Monmouth Square.” Local officials, tenants and representatives of New York-based real estate developer Kushner Companies gathered at the historic mall in Eatontown on Thursday to break ground on the $500 million redevelopment project. The event signified the beginning of the enclosed mall’s metamorphosis into an open-air destination with a mix of stores, restaurants, apartments and 115,000 square feet of m…