treewide: remove maintainership of ma27 from a few packages

Those are packages I don't use anymore for a longer time and I therefore
don't think that listing me as maintainer is a good idea. If those
should be removed now, I'd be fine with that.

SuperSandro2000 will take care of a few packages[1].

[1] https://github.com/NixOS/nixpkgs/pull/108126#pullrequestreview-560599381

pkgs/applications/science/math/geogebra/default.nix

@@ -27,7 +27,7 @@ let
       calculus in one easy-to-use package.
     '';
     homepage = "https://www.geogebra.org/";
-    maintainers = with maintainers; [ ma27 ];
+    maintainers = with maintainers; [ ];
     license = with licenses; [ gpl3 cc-by-nc-sa-30 geogebra ];
     platforms = with platforms; linux ++ darwin;
     hydraPlatforms = [];