Add https://search.ballardini.de

Close #643 
From @lballardini

Author: ononoki1

searxinstances/instances.yml

@@ -18,6 +18,7 @@ https://paulgo.io: {}
 https://priv.au: {}
 https://s.mble.dk: {}
 https://search.080609.xyz: {}
+https://search.ballardini.de: {}
 https://search.blitzw.in: {}
 https://search.bus-hit.me: {}
 https://search.canine.tools: {}