Remove appimage.

nodes/hosts/common/system/appimage.nix

@@ -1,9 +0,0 @@
-{ pkgs, ... }: {
-  programs.appimage.enable = true;
-  programs.appimage.binfmt = true;
-  programs.appimage.package = pkgs.appimage-run.override { extraPkgs = pkgs: [
-    pkgs.haskellPackages.gi-ayatana-appindicator3
-    pkgs.haskellPackages.happindicator3
-  ]; };
-}
-