“The Cher Show”, a new bio-musical, never tries to be anything it is not, wholly owning its own wry silliness and decadent camp while honoring the pop legend whose story it quite legibly tells, and remaining blissfully entertaining.  The show delivers exactly what it needs to—from songs to sequins—the costumes get entrance applause, and Stephanie J. Block embodies Cher in a career-high performance.  Capturing the self-effacing spirit and pizzazz of its pop diva, “The Cher Show” is aptly titled.