There's a lot going on in the new Birds of Prey and the Fantabulous Emancipation of One Harley Quinn posted Warner Bros. released on Wednesday afternoon. The upcoming Cathy Yan-directed comic book pic stars Margot Robbie, who is reprising her role as Harley Quinn, as well as Ewan McGregor, Mary Elizabeth Winstead, Rosie Perez, Jurnee Smollett-Bell, Chris Messina, and Ella Jay Basco. Where to begin? Well, art history nerds (yours truly included) will love that this poster is riffing on Botticelli's 15th century artwork "The Birth of Venus." Instead of the goddess Venus, it's Harley …