All routes are now installed in a custom netbird routing table.
Management and wireguard traffic is now marked with a custom fwmark.
When the mark is present the traffic is routed via the main routing table, bypassing the VPN.
When the mark is absent the traffic is routed via the netbird routing table, if:
- there's no match in the main routing table
- it would match the default route in the routing table
IPv6 traffic is blocked when a default route IPv4 route is configured to avoid leakage.
Small code cleaning in the iface package. These changes necessary to
get a clean code in case if we involve more platforms. The OS related
functions has been distributed into separate files and it has been
mixed with not OS related logic. The goal is to get a clear picture
of the layer between WireGuard and business logic.
