chore(all): return concrete types, accept interfaces

- Remove exported interfaces unused locally
- Define interfaces to accept arguments
- Return concrete types, not interfaces

internal/netlink/address.go

@@ -4,14 +4,6 @@ import "github.com/vishvananda/netlink"
 
 type Addr = netlink.Addr
 
-var _ Addresser = (*NetLink)(nil)
-
-type Addresser interface {
-	AddrList(link netlink.Link, family int) (
-		addresses []netlink.Addr, err error)
-	AddrAdd(link netlink.Link, addr *netlink.Addr) error
-}
-
 func (n *NetLink) AddrList(link Link, family int) (
 	addresses []Addr, err error) {
 	return netlink.AddrList(link, family)