[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_android.go

@@ -0,0 +1,24 @@
+package iface
+
+import (
+	"fmt"
+)
+
+// CreateOnAndroid creates a new Wireguard interface, sets a given IP and brings it up.
+// Will reuse an existing one.
+func (w *WGIface) CreateOnAndroid(routes []string, dns string, searchDomains []string) error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	cfgr, err := w.tun.Create(routes, dns, searchDomains)
+	if err != nil {
+		return err
+	}
+	w.configurer = cfgr
+	return nil
+}
+
+// Create this function make sense on mobile only
+func (w *WGIface) Create() error {
+	return fmt.Errorf("this function has not implemented on this platform")
+}