refactor: move AuthResult to Auth/Types.hs module

The `AuthResult` type does not belong to AppState
module. This commit refactor this by moving it to
a new module `Auth/Types.hs`.

src/PostgREST/Auth/Types.hs

@@ -0,0 +1,13 @@
+module PostgREST.Auth.Types
+  ( AuthResult (..) )
+  where
+
+import qualified Data.Aeson        as JSON
+import qualified Data.Aeson.KeyMap as KM
+import qualified Data.ByteString   as BS
+
+-- | Parse result for JWT Claims
+data AuthResult = AuthResult
+  { authClaims :: KM.KeyMap JSON.Value
+  , authRole   :: BS.ByteString
+  }