[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/messages/message_test.go

@@ -0,0 +1,43 @@
+package messages
+
+import (
+	"testing"
+)
+
+func TestMarshalHelloMsg(t *testing.T) {
+	peerID := []byte("abdFAaBcawquEiCMzAabYosuUaGLtSNhKxz+")
+	bHello, err := MarshalHelloMsg(peerID, nil)
+	if err != nil {
+		t.Fatalf("error: %v", err)
+	}
+
+	receivedPeerID, _, err := UnmarshalHelloMsg(bHello[SizeOfProtoHeader:])
+	if err != nil {
+		t.Fatalf("error: %v", err)
+	}
+	if string(receivedPeerID) != string(peerID) {
+		t.Errorf("expected %s, got %s", peerID, receivedPeerID)
+	}
+}
+
+func TestMarshalTransportMsg(t *testing.T) {
+	peerID := []byte("abdFAaBcawquEiCMzAabYosuUaGLtSNhKxz+")
+	payload := []byte("payload")
+	msg, err := MarshalTransportMsg(peerID, payload)
+	if err != nil {
+		t.Fatalf("error: %v", err)
+	}
+
+	id, respPayload, err := UnmarshalTransportMsg(msg[SizeOfProtoHeader:])
+	if err != nil {
+		t.Fatalf("error: %v", err)
+	}
+
+	if string(id) != string(peerID) {
+		t.Errorf("expected %s, got %s", peerID, id)
+	}
+
+	if string(respPayload) != string(payload) {
+		t.Errorf("expected %s, got %s", payload, respPayload)
+	}
+}