Stardust has a really good idea for a movie: the rise of an insecure musician who strives for fame but, at the same time, is scared of how his lack of identity will ruin him.  If the movie was about an ambiguous celebrity, director Gabriel Range (Death of a President) could’ve had a lot of room to explore the anxieties of fame.  Unfortunately, he’s desperate to crowbar these dilemmas into an unqualified and unauthorized biopic…