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/family.go

@@ -2,8 +2,6 @@ package netlink
 
 import (
 	"fmt"
-
-	"github.com/vishvananda/netlink"
 )
 
 const (
@@ -24,16 +22,3 @@ func FamilyToString(family int) string {
 		return fmt.Sprint(family)
 	}
 }
-
-func (n *NetLink) IsWireguardSupported() (ok bool, err error) {
-	families, err := netlink.GenlFamilyList()
-	if err != nil {
-		return false, fmt.Errorf("listing gen 1 families: %w", err)
-	}
-	for _, family := range families {
-		if family.Name == "wireguard" {
-			return true, nil
-		}
-	}
-	return false, nil
-}