Amazon’s $75 million close-up on the First Lady made back less than a quarter of its budget, but it was enough for Ratner to plan a docuseries follow-up.Melania Trump in ‘Melania’Credit: Amazon MGM StudiosKey PointsBrett Ratner has announced a docuseries follow-up to his documentary Melania.Amazon paid $75 million for his documentary on First Lady Melania Trump, which premiered in January.The film earned back just $16.3 million after a five-week…