Add 'unlisted' key

unlisted posts will still be put in the normal place but
not added to the gallery or rss feed

make-pages/Info.hs

@@ -45,6 +45,8 @@ data Info =
     updates     :: ![Update],
     -- | if false, don't show updated emblem even if @updates@ is non-empty
     showUpdated :: !Bool,
+    -- | hide from gallery view
+    unlisted    :: !Bool,
     title       :: !Text,
     artist      :: !(Maybe Artist), -- nothing = me, obv
     nsfwOnly    :: !Bool,
@@ -245,6 +247,7 @@ instance FromYAML Info where
          <*>  m .:? "sort"         .!= ""
          <*> (m .:? "updates" >>= updateList)
          <*>  m .:? "show-updated" .!= True
+         <*>  m .:? "unlisted"     .!= False
          <*>  m .:  "title"
          <*>  m .:? "artist"
          <*>  m .:? "nsfw-only" .!= False