A prime asset in the Village of Roslyn’s ongoing renaissance has traded hands. The mixed-use property known as the Roslyn Lumber Yard has sold for $31 million, the village’s largest-ever transaction, according to the brokers on the deal. GB Family Holdings, a Melville-based commercial real estate investment firm and an affiliate of Fairfield Properties principal Gary Broxmeyer, purchased the 25-unit apartment building with 14,000 square feet of retail space at 17-21 Lumbe