dh systemd: use newer --no-start flag and autogen postinst

dh systemd: use newer --no-start flag and autogen postinst

With that, only comments change from our manual implementation, e.g.,
looking at diffoscope output from a build before and with this
change:

@@ -15,28 +15,27 @@
         systemctl --system daemon-reload >/dev/null || true
         deb-systemd-invoke $dh_action "$unit"
     fi
   ;;

 esac

-# Copied from dh_installsystemd/12.1.1
+# Automatically added by dh_installsystemd/13.11.4
 if [ "$1" = "configure" ] || [ "$1" = "abort-upgrade" ] || [ "$1" = "abort-deconfigure" ] || [ "$1" = "abort-remove" ] ; then
- # This will only remove masks created by d-s-h on package removal.
+ # The following line should be removed in trixie or trixie+1
  deb-systemd-helper unmask 'lxcfs.service' >/dev/null || true

  # was-enabled defaults to true, so new installations run enable.
  if deb-systemd-helper --quiet was-enabled 'lxcfs.service'; then
          # Enables the unit on first installation, creates new
          # symlinks on upgrades if the unit file has changed.
          deb-systemd-helper enable 'lxcfs.service' >/dev/null || true
  else
          # Update the statefile to add new symlinks (if any), which need to be
          # cleaned up on purge. Also remove old symlinks.
          deb-systemd-helper update-state 'lxcfs.service' >/dev/null || true
  fi
 fi
+# End automatically added section

-# dh_installsystemd cannot do a reload, you can only choose between stop-start,
-# restart and try-restart. NONE of which are acceptable!

 exit 0

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>