Bullseye alongside Bookworm (#61)

* revert to bullseye.

* add bookworm.

* add bookworm to variants.

* include xf86-video-dummy because the remote git instance is offline.

* fix configure.

runtime/dbus

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+if [ ! -d /var/run/dbus ]; then
+  mkdir -p /var/run/dbus
+fi
+
+if [ -f /var/run/dbus/pid ]; then
+  rm -f /var/run/dbus/pid
+fi
+
+/usr/bin/dbus-daemon --nofork --print-pid --config-file=/usr/share/dbus-1/system.conf

runtime/supervisord.dbus.conf

@@ -0,0 +1,9 @@
+[program:dbus]
+environment=HOME="/root",USER="root"
+command=/usr/bin/dbus
+autorestart=true
+priority=100
+user=root
+stdout_logfile=/dev/stderr
+stdout_logfile_maxbytes=0
+redirect_stderr=true