Richard Hanus isn’t a diehard theater geek. And the immigration system doesn’t normally make for entertainment.But in the latest demonstration that all the world’s a stage, Hanus, who has worked visa, citizenship and deportation cases for more than 25 years, is now featured in an off-Broadway production.One of his cases is the inspiration for “The Courtroom,” a re-enactment arranged by a Tony-and Emmy-nominated actor and director that debuted earlier this year in New York and has been …