debian: link more stuff from factory

CUPS is pulled in by GNOME packages and fails without configs.
Need /etc/skel to create users from GNOME's GUI, and to have the homedir shellery set up correctly.
Workaround for adduser/deluser bugs.
PackageKit is needed otherwise GNOME stalls logout/reboot if it doesn't run.
Bash completion files used by run0/systemd-run.

Author: bluca

mkosi.conf.d/debian/mkosi.extra/usr/lib/tmpfiles.d/etc-debian.conf

@@ -11,3 +11,18 @@ L? /etc/nftables.conf
 
 # Very basic stuff like awk and which is managed through alternatives
 L? /etc/alternatives
+
+# CUPS is pulled in by GNOME, and fails if the configs are not there
+L? /etc/cups
+
+# Needed to create users by GNOME's GUI
+L? /etc/skel
+# These can be dropped once https://bugs.debian.org/1108017 is fixed
+L? /etc/adduser.conf
+L? /etc/deluser.conf
+
+# PackageKit does not run without /etc/PackageKit/ and GNOME stalls logout/reboot if it doesn't run
+L? /etc/PackageKit
+
+# TODO: drop once https://github.com/scop/bash-completion/pull/1399 is merged, needed for shell completion of sd-run/run0
+L? /etc/bash_completion.d