Handle peer interface config change (#348)

Before this change, NetBird Agent wasn't handling
peer interface configuration changes dynamically.
Also, remote peer configuration changes have
not been applied (e.g. AllowedIPs changed).
Not a very common cause, but still it should be handled.
Now, Agent reacts to PeerConfig changes sent from the
management service and restarts remote connections
if AllowedIps have been changed.

client/internal/proxy/proxy.go

@@ -21,7 +21,7 @@ const (
 type Config struct {
 	WgListenAddr string
 	RemoteKey    string
-	WgInterface  iface.WGIface
+	WgInterface  *iface.WGIface
 	AllowedIps   string
 	PreSharedKey *wgtypes.Key
 }