[Appimage] Adds appimage support with libicu

system/features/appimage.nix

@@ -0,0 +1,12 @@
+{ pkgs, ... }:
+{
+  programs.appimage = {
+    enable = true;
+    binfmt = true;
+    package = pkgs.appimage-run.override {
+      extraPkgs = pkgs: [
+        pkgs.icu
+      ];
+    };
+  };
+}