More granular allow WireGuard LAN

[jwijenbergh]

The problem is that WireGuard LAN by default is blocked. This is great for security but makes it a bit difficult for usability. It would be cool to e.g.

• maybe let the user still allow certain ranges, e.g. for docker: 172.17. 0.0/16
• Allow RFC1918 routes by default. Currently the LAN toggle is whether or not to add the "suppress prefixlength 0" rule. See https://ro-che.info/articles/2021-02-27-linux-routing for a good recap of what this does
• allow LAN on a network basis, e.g. by SSID or WIFI settings (e.g. allow wireguard LAN on enterprise networks)
• allow certain applications to go outside of the VPN (difficult to do securely)