feat: add various system and theme icons, configuration files, and support assets

squashfs-root/usr/lib/systemd/system/user@.service.d/10-login-barrier.conf

@@ -0,0 +1,14 @@
+#  SPDX-License-Identifier: LGPL-2.1-or-later
+#
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+# Make sure user instances are started after logins are allowed. However this
+# is not desirable for user@0.service since root should be able to log in
+# earlier during the boot process especially if something goes wrong.
+After=systemd-user-sessions.service