Support tun interface

[ameir]

Thanks for the great work!

This project would enable additional use cases if it supported creating a tun interface on the client side so that users could create routes, and use Masque similar to a VPN (e.g. see 1.1.1.1).

The INVISV relay seemed similar to what I am looking for, but I'm unsure of the implementation on the client side of things. If there's an existing way to route all client-side traffic, that would be great.