It was a sunny day on a spot that has seen its share of darkness. The Old Colony Housing Development, one of the icons of the old South Boston, is undergoing a dramatic facelift, and officials today celebrated the completion of the first phase of the redevelopment - which includes a large new apartment building, a new learning center, and three-story townhouse homes that Boston City Councilor Billy Linehan said “look like they should be in a seaside resort.’’ Old Colony has long been celebrated for its village-like atmosphere and large families, while simultaneously maligned for a shadowy underbelly of crime and substance abuse. The liquor store that was the alleged headquarters for Whitey Bulger’s organized crime ring is just across the street.