Jenna Paulette is premiering the music video for her new song "Slow Dancing. waiting for my grandfather to bring the cows around." She told songwriter Ashley Gorley that story, and he asked. Set in the 18th Century and starring Emma Stone, Rachel Weisz and Broadchurch’s Olivia Colman, it’s full of backstabbing royalty, bizarre love triangles and a duck race filmed in slow motion. Hits. Luhrmann, who started his career in…