Not much time may be left for Boston Market fans who want to get a fix of chicken carver sandwiches, rotisserie ribs or mashed potatoes at the once-popular fast-casual chain that has been based in Golden for nearly three decades. Boston Market is down to three locations in Colorado — Westminster, Aurora and Colorado Springs — and its owner, Engage Brands, has let a big stack of bills pile up from its landlords, vendors, employees and even the state of Colorado. Last week, the Colorado Department of Revenue posted big notices on the doors of the company’s headquarters and its three remaining restaurants announcing an asset seizure.