Move signals to their own package

Author: ajnsit

spago.dhall

@@ -9,9 +9,7 @@ You can edit this file as you like.
   , "effect"
   , "either"
   , "foldable-traversable"
-  , "free"
   , "identity"
-  , "lazy"
   , "maybe"
   , "newtype"
   , "prelude"