move modules into subdir

modules/installer.nix

@@ -0,0 +1,40 @@
+{ lib
+, pkgs
+, ...
+}: {
+  systemd.tmpfiles.rules = [
+    "d /var/shared 0777 root root - -"
+  ];
+  services.openssh.settings.PermitRootLogin = "yes";
+  system.activationScripts.root-password = ''
+    mkdir -p /var/shared
+    ${pkgs.pwgen}/bin/pwgen -s 16 1 > /var/shared/root-password
+    echo "root:$(cat /var/shared/root-password)" | chpasswd
+  '';
+  hidden-ssh-announce = {
+    enable = true;
+    script = pkgs.writers.writeDash "write-hostname" ''
+      mkdir -p /var/shared
+      echo "$1" > /var/shared/onion-hostname
+      ${pkgs.jq}/bin/jq -nc \
+        --arg password "$(cat /var/shared/root-password)" \
+        --arg address "$(cat /var/shared/onion-hostname)" '{
+          password: $password, address: $address
+        }' > /var/shared/login.info
+      cat /var/shared/login.info |
+        ${pkgs.qrencode}/bin/qrencode -t utf8 > /var/shared/qrcode.utf8
+      cat /var/shared/login.info |
+        ${pkgs.qrencode}/bin/qrencode -t png > /var/shared/qrcode.png
+    '';
+  };
+  services.getty.autologinUser = lib.mkForce "root";
+  programs.bash.interactiveShellInit = ''
+    if [ "$(tty)" = "/dev/tty1" ]; then
+      until test -e /var/shared/qrcode.utf8; do sleep 1; done
+      cat /var/shared/qrcode.utf8
+    fi
+  '';
+  formatConfigs.install-iso = {
+    isoImage.squashfsCompression = "zstd -Xcompression-level 1";
+  };
+}