Deep in the rainforests of Afghanistan, two soldiers on a top-secret mission collide with Somali pirates, a horndog missionary, a depressed parrot, and more, egged on by a playwright struggling to tell a story that may not even be his to tell. “The Ridiculous Darkness” casts a timely, absurdist eye on cultural and economic colonialism in this send-up of the classic “Heart of Darkness” and its hallucinatory 1979 film adaptation, “Apocalypse Now.”