IPV6 - Docker mod for Wireguard

This mod adds IPV6 support to Wireguard.

In Wireguard docker arguments, set an environment variable DOCKER_MODS=xefir/mods:wireguard-ipv6

If adding multiple mods, enter them in an array separated by |, such as DOCKER_MODS=xefir/mods:wireguard-ipv6|linuxserver/mods:server-mod2

New parameters

Parameter	Function
`-e INTERNAL_SUBNET_IPV4=10.13.13.0`	Internal IPv4 subnet for the wireguard and server and peers (only change if it clashes). Used in server mode.
`-e INTERNAL_SUBNET_IPV6=fd42:42:42::0`	Internal IPv6 subnet for the wireguard and server and peers (only change if it clashes). Used in server mode.