After significant turnover at the top, the Boston Society of Architects has named a new leader. Longtime staffer Eric White has been appointed executive director. White has been part of the management team at the BSA since 2006, most recently as managing director. He has been involved in new initiatives the group has undertaken since then, the BSA said. Prior to joining the nonprofit, White directed programs at Old Sturbridge Village. Also continuing in a senior leadership role at the BSA is managing…