By Nora Eckert DETROIT, Dec 16 (Reuters) - Ford CEO Jim Farley walked through Ford’s Michigan design studio Monday afternoon, reflecting on how he was about to wipe out thousands of work hours on electric vehicles that he and his team had hoped would revolutionize the American auto industry. Shortly after, his company announced it would kill several of those battery-powered models and take a $19.5 billion writedown on EV-related assets. It marked the industry’s ​biggest electric-vehicle retreat since U.S ...