PARK CITY, Ut. - Documentaries need not be lengthy to explore a fascinating subject, as I learned at the “Documentary Shorts Program 2” at Sundance. In “All That Perishes at the Edge of Land,” filmmaker Hira Nabi’s camera magnificently captures the “ship breaking” industry of Pakistan, which employs the poorest of the poor to disassemble obsolete carrier vessels for scrap. The ships grounded ashore in the region