On a recent weekday morning, the parking lots at Foxwoods Resort Casino were crowded with cars registered in Massachusetts, parked there by patrons who drove an hour or more to play the games, but in a few years will have the same Las Vegas-style gambling much closer to home. Foxwoods is fighting to keep those Bay State customers, or as many as possible. The tribal casino, now 20 years old, is expanding with a new outlet mall.