Add a Nginx reverse proxy to combine all the used ports into one single port

This will allow this web UI to sit nicely behind a reverse proxy.

Dynamically set the ports used for the
- VNC service
- noVNC service
- Pulseaudio socket
- VNC audio transport websocket

Remove all mentions of the above used ports in the Dockerfile.

overlay/etc/supervisor.d/steam.ini

@@ -6,7 +6,7 @@ autorestart=true
 # Retry a restart a few times.
 #   This allows this container to start up before X is ready and restart the process until it becomes available.
 #   Each restart will have a small delay of a few seconds. So 50 attempts should be a few mins.
-startretries=50 
+startretries=50
 priority=50
 user=%(ENV_USER)s
 directory=/home/%(ENV_USER)s

overlay/etc/supervisor.d/vnc.ini

@@ -18,7 +18,8 @@ autostart=false
 autorestart=true
 priority=30
 user=%(ENV_USER)s
-command=/opt/noVNC/utils/launch.sh --vnc localhost:%(ENV_PORT_VNC)s --listen %(ENV_PORT_NOVNC_WEB)s
+# /opt/noVNC/utils/launch.sh --vnc localhost:${PORT_VNC} --listen ${PORT_NOVNC_SERVICE}
+command=/opt/noVNC/utils/launch.sh --vnc localhost:%(ENV_PORT_VNC)s --listen %(ENV_PORT_NOVNC_SERVICE)s
 environment=HOME="/home/%(ENV_USER)s",USER="%(ENV_USER)s"
 stopsignal=INT
 stdout_logfile=/home/%(ENV_USER)s/.cache/log/novnc.log
@@ -27,3 +28,20 @@ stdout_logfile_backups=7
 stderr_logfile=/home/%(ENV_USER)s/.cache/log/novnc.err.log
 stderr_logfile_maxbytes=10MB
 stderr_logfile_backups=7
+
+[program:vncproxy]
+autostart=false
+autorestart=true
+priority=30
+numprocs=1
+startsecs=0
+user=%(ENV_USER)s
+command=/usr/sbin/nginx -c /opt/noVNC/nginx.conf
+environment=HOME="/home/%(ENV_USER)s",USER="%(ENV_USER)s"
+stopsignal=INT
+stdout_logfile=/home/%(ENV_USER)s/.cache/log/vncproxy.log
+stdout_logfile_maxbytes=10MB
+stdout_logfile_backups=7
+stderr_logfile=/home/%(ENV_USER)s/.cache/log/vncproxy.err.log
+stderr_logfile_maxbytes=10MB
+stderr_logfile_backups=7