chore(netlink): separate linux only and OS independent code

- Move `Addr` and its `String` method to `types.go`
- Move `IsWireguardSupported` to `wireguard.go` to have `family.go` OS independant
- Remove dependency on vishvananda/netlink in `ipv6.go`
- Move `Link` to `types.go`
- Move `Route` to `types.go`
- Move `Rule` and its `String` method to `types.go`

internal/netlink/ipv6.go

@@ -2,8 +2,6 @@ package netlink
 
 import (
 	"fmt"
-
-	"github.com/vishvananda/netlink"
 )
 
 func (n *NetLink) IsIPv6Supported() (supported bool, err error) {
@@ -15,7 +13,7 @@ func (n *NetLink) IsIPv6Supported() (supported bool, err error) {
 	var totalRoutes uint
 	for _, link := range links {
 		link := link
-		routes, err := n.RouteList(&link, netlink.FAMILY_V6)
+		routes, err := n.RouteList(&link, FamilyV6)
 		if err != nil {
 			return false, fmt.Errorf("listing IPv6 routes for link %s: %w",
 				link.Name, err)