add barebones installer, not tested yet

installer.nix

@@ -0,0 +1,25 @@
+{ config, lib, pkgs, ... }:
+{
+  systemd.tmpfiles.rules = [
+    "d /var/shared 0777 root root - -"
+  ];
+  services.openssh.settings.PermitRootLogin = "yes";
+  system.activationScripts.root-password = ''
+    ${pkgs.pwgen}/bin/pwgen -s 16 1 > /var/shared/root-password
+    echo "root:$(cat /var/shared/root-password)" | chpasswd
+  '';
+  hidden-announce = {
+    enable = true;
+    script = pkgs.writers.writeDash "write-hostname" ''
+      echo "$1" > /var/shared/onion-hostname
+    '';
+  };
+  services.getty.autologinUser = lib.mkForce "root";
+  programs.bash.interactiveShellInit = ''
+    if [ "$(tty)" = "/dev/tty1" ]; then
+      echo "ssh://root:$(cat /var/shared/root-password)@$(cat /var/shared/onion-hostname)"
+    fi
+  '';
+  # TODO find a place to put this
+  # isoImage.squashfsCompression = "zstd -Xcompression-level 1";
+}