Create Note outbox handler, not in use yet

I wrote a function handleOutboxNote that's supposed to do the whole outbox POST
handler process. There's an outbox item table in the DB now, I adapted things
in various source files. Ticket comment federation work is still in progress.

src/Data/Either/Local.hs

@@ -1,6 +1,6 @@
 {- This file is part of Vervis.
  -
- - Written in 2016 by fr33domlover <fr33domlover@riseup.net>.
+ - Written in 2016, 2019 by fr33domlover <fr33domlover@riseup.net>.
  -
  - ♡ Copying is an act of love. Please copy, reuse and share.
  -
@@ -16,6 +16,7 @@
 module Data.Either.Local
     ( maybeRight
     , maybeLeft
+    , requireEither
     )
 where
 
@@ -28,3 +29,9 @@ maybeRight (Right b) = Just b
 maybeLeft :: Either a b -> Maybe a
 maybeLeft (Left a)  = Just a
 maybeLeft (Right _) = Nothing
+
+requireEither :: Maybe a -> Maybe b -> Either Bool (Either a b)
+requireEither Nothing  Nothing   = Left False
+requireEither (Just _) (Just _)  = Left True
+requireEither (Just x) Nothing   = Right $ Left x
+requireEither Nothing  (Just y)  = Right $ Right y