treewide: remove ma27 from the maintainer-list of a few packages

These are all packages that I stopped using and hence just create noise
in my inbox for each change affecting them and let's face it, while I
still enjoy contributing to nixpkgs, it doesn't really make sense to be
listed there if I can't do much anyways.

Each of these packages can be taken over by someone or removed if
people think that's reasonable.

Of course, if other maintainers face issues, I can answer some questions
if needed & possible.

pkgs/development/python-modules/pybase64/default.nix

@@ -24,6 +24,6 @@ buildPythonPackage rec {
     description = "Fast Base64 encoding/decoding";
     homepage = "https://github.com/mayeut/pybase64";
     license = licenses.bsd2;
-    maintainers = with maintainers; [ ma27 ];
+    maintainers = with maintainers; [ ];
   };
 }