[mod] disable wallhaven by default

searx/settings.yml

@@ -2546,6 +2546,7 @@ engines:
     engine: wallhaven
     # api_key: abcdefghijklmnopqrstuvwxyz
     shortcut: wh
+    disabled: true
 
     # wikimini: online encyclopedia for children
     # The fulltext and title parameter is necessary for Wikimini because