explicit exports (#1719)

* explicit exports

* more empty exports

* add exports

* reorder

* use correct ControlProtocol type for xftp router

---------

Co-authored-by: Evgeny @ SimpleX Chat <259188159+evgeny-simplex@users.noreply.github.com>

src/Simplex/FileTransfer/Server/Control.hs

@@ -1,7 +1,10 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE OverloadedStrings #-}
 
-module Simplex.FileTransfer.Server.Control where
+module Simplex.FileTransfer.Server.Control
+  ( ControlProtocol (..),
+  )
+where
 
 import qualified Data.Attoparsec.ByteString.Char8 as A
 import Simplex.FileTransfer.Protocol (XFTPFileId)