Adds convenient Amazon ElasticSearch Service authentication to Bloodhound.
env <- newEnv region Discover
let auth = env ^. envAuth
let hook req = withAuth auth $ ae ->
either (liftIO . throwIO) return =<< amazonkaAuthHook ae region req
mgr <- newManager tlsManagerSettings
let bhe = (mkBHEnv server mgr) { bhRequestHook = hook }