[client] Eliminate UDP proxy in user-space mode (#2712)

In the case of user space WireGuard mode, use in-memory proxy between the TURN/Relay connection and the WireGuard Bind. We keep the UDP proxy and eBPF proxy for kernel mode.

The key change is the new wgproxy/bind and the iface/bind/ice_bind changes. Everything else is just to fulfill the dependencies.

client/iface/iface_create_darwin.go

@@ -0,0 +1,41 @@
+//go:build !ios
+
+package iface
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/cenkalti/backoff/v4"
+)
+
+// Create creates a new Wireguard interface, sets a given IP and brings it up.
+// Will reuse an existing one.
+// this function is different on Android
+func (w *WGIface) Create() error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	backOff := &backoff.ExponentialBackOff{
+		InitialInterval: 20 * time.Millisecond,
+		MaxElapsedTime:  500 * time.Millisecond,
+		Stop:            backoff.Stop,
+		Clock:           backoff.SystemClock,
+	}
+
+	operation := func() error {
+		cfgr, err := w.tun.Create()
+		if err != nil {
+			return err
+		}
+		w.configurer = cfgr
+		return nil
+	}
+
+	return backoff.Retry(operation, backOff)
+}
+
+// CreateOnAndroid this function make sense on mobile only
+func (w *WGIface) CreateOnAndroid([]string, string, []string) error {
+	return fmt.Errorf("this function has not implemented on this platform")
+}