A local government’s charter is a big deal.“It is your municipal constitution,” Longboat Key Town Attorney Maggie Mooney said. “It’s going to describe where your boundaries are. It’s going to talk about elected official’s seats, terms and qualifications. It’s going to talk about what your fiduciary responsibilities are. You’re going to have a description of your legislative body.”The town of Longboat Key operates under the council-manager form o…