Takeout cups and clamshell containers usually have a very short life: They hold a meal, get tossed in the trash, and then end up in a landfill. In Hilo, Hawaiʻi, however, that routine could soon look very different. Later this year, residents ordering food to go may be able to borrow stainless-steel containers much like they would check out a library book — free to use, so long as they return them. What's happening? According to Honolulu Civil B…