By: Mark Barber Prolific documentarian Alex Gibney’s latest film is an insightful–if perhaps overlong–two-hour reminder of the controversial Church of Scientology.  Based on and working extensively off of Lawrence Wright’s 2013 book Going Clear: Scientology, Hollywood, and the Prison of Belief, Gibney traces Scientology’s history from its very beginnings with its erratic and odd founder L. Ron Hubbard to the assimilation of Hollywood celebrities into the cult. Perhaps most distressingly, however, is Gibney’s chosen slate…