Run x11vnc as root inside the container

overlay/etc/supervisor.d/vnc.ini

@@ -3,7 +3,7 @@
 priority=30
 autostart=false
 autorestart=true
-user=%(ENV_USER)s
+user=root
 command=/usr/bin/start-x11vnc.sh
 environment=HOME="/home/%(ENV_USER)s",USER="%(ENV_USER)s",DISPLAY="%(ENV_DISPLAY)s",PORT_VNC="%(ENV_PORT_VNC)s"
 stopsignal=INT