cwality-maps: remove unused parameters

the substitutions + templating seems reasonably powerfull, let's see how
far we get without custom-made specific things.

cwality-maps/Main.hs

@@ -58,11 +58,8 @@ instance FromHttpApiData JsonFilename where
 newtype Tag = Tag Text
   deriving (Generic, FromJSON)
 
-data MapParams = MapParams
-  { contentWarnings :: [Tag]
-  , backUrl         :: Text
-  , exitUrl         :: Maybe Text
-  , substs          :: Map Text Text
+newtype MapParams = MapParams
+  { substs          :: Map Text Text
   } deriving (Generic, FromJSON)
 
 instance FromHttpApiData MapParams where