Photo-Illustration: Vulture; Photos: Earl Gibson III/Penske Media via Getty Images, MGM/Everett Collection In a departure that’s surely shaken and stirred up chatter around Hollywood, the head of Amazon MGM Studios Jennifer Salke is leaving the company. In a letter sent to employees Thursday afternoon, Amazon exec Mike Hopkins broke the news, saying, “Jen will step down from her role as Head of Amazon MGM Studios in order to start a new production entity,” while also earning an “overall first-