The Mavericks franchise’s search for a new CEO has produced a remarkable hire. A Hall of Fame hire, no less. Legendary NBA executive and Naismith Memorial Basketball Hall of Famer Rick Welts has agreed to become the Mavericks’ president and CEO, replacing the retiring Cynt Marshall, he told The Dallas Morning News. Welts, who turns 72 on Jan. 21, most recently was the Golden State Warriors’ …