With uncrowded sands and small-town vibes, a North Carolina beach leads a new list of America’s calmest shores.Beach front houses in Holden Beach, North Carolina.Credit: zimmytws/Getty ImagesThere are many ways to judge a beach: the softness of its sand, the clarity of its water, the quality of the surf, or nearby activities and dining. But for those seeking a peaceful escape, free from crowds and rogue volleyballs, tranquility is key. And when …