add a websocket to ssh endpoint

[tionis]

Support some websocket proxy (e.g. like huproxy) that can be used as jumphost into pico.sh services.
This would allow users in restrictive network requirements (e.g. public wifi) to still access pico.sh's services.
To prevent misuse the jump host targets should be limited to pico.sh services. If a user wants to jump further they can do a two-hop jump via tuns.sh private tcp alias and some node at home or similar.