Dozens of families are illegally living in dilapidated trailers in the shadow of CitiField — draining off water from fire hydrants and swiping electricity while running black-market auto-repair shops. The unsightly gypsy-like encampment underneath the Whitestone Expressway, populated largely by Spanish-speaking migrants, has become a nightmare for residents and merchants along a stretch of Queens in the shadow of the New York Mets home field — and yet the city has done nothing, locals told The