[relay] Feature/relay integration (#2244)

This update adds new relay integration for NetBird clients. The new relay is based on web sockets and listens on a single port.

- Adds new relay implementation with websocket with single port relaying mechanism
- refactor peer connection logic, allowing upgrade and downgrade from/to P2P connection
- peer connections are faster since it connects first to relay and then upgrades to P2P
- maintains compatibility with old clients by not using the new relay
- updates infrastructure scripts with new relay service

relay/testec2/start_msg.go

@@ -0,0 +1,39 @@
+//go:build linux || darwin
+
+package main
+
+import (
+	"bytes"
+	"encoding/gob"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+)
+
+type StartIndication struct {
+	Started      time.Time
+	TransferSize int
+}
+
+func NewStartInidication(started time.Time, transferSize int) []byte {
+	si := StartIndication{
+		Started:      started,
+		TransferSize: transferSize,
+	}
+
+	var data bytes.Buffer
+	err := gob.NewEncoder(&data).Encode(si)
+	if err != nil {
+		log.Fatal("encode error:", err)
+	}
+	return data.Bytes()
+}
+
+func DecodeStartIndication(data []byte) StartIndication {
+	var si StartIndication
+	err := gob.NewDecoder(bytes.NewReader(data)).Decode(&si)
+	if err != nil {
+		log.Fatal("decode error:", err)
+	}
+	return si
+}