Alison Herman TV Critic Amid a horrifying month in world news, it’s a relief to reenter the world of “The Gilded Age,” where problems are something to be gossiped about over lawn tennis in Newport. In Julian Fellowes’ opulent, HBO-funded take on 19th century New York, the recently concluded Civil War takes up a fraction of the real estate devoted to the Opera War, a brewing fight for patronage and prestige between the establishment-favored Academy of Music and the upstart Metropolitan.