moved deviations living under horizon to common shared folder

modules/nixos-modules/packages/default.nix

@@ -0,0 +1,17 @@
+{pkgs, ...}: {
+  nixpkgs.overlays = [
+    (final: prev: {
+      webtoon-dl =
+        pkgs.callPackage
+        ./webtoon-dl.nix
+        {};
+    })
+    # TODO: this package always needs to be called with the --in-process-gpu flag for some reason, can we automate that?
+    (final: prev: {
+      prostudiomasters =
+        pkgs.callPackage
+        ./prostudiomasters.nix
+        {};
+    })
+  ];
+}