nix/overlays: add more python packages to qtile

_psutil_ is required with my current config, and the others are inserted
precautiously.

nix/overlays/overrides.nix

@@ -32,5 +32,16 @@ in {
   # TODO: facetimehd is currfently broken (https://github.com/NixOS/nixpkgs/pull/72804)
   facetimehd-firmware = super.hello;
 
-  qtile = self.nixpkgs-master.qtile;
+  qtile = self.nixpkgs-master.qtile.overrideAttrs(oldAttrs: {
+    pythonPath = oldAttrs.pythonPath ++ (with self.python37Packages; [
+      psutil
+      dbus-python
+      pyxdg
+      mpd2
+      # python-wifi
+      # iwlib
+      dateutil
+      keyring
+    ]);
+  });
 }