[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/main.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/relay/cmd"
+)
+
+func main() {
+	if err := cmd.Execute(); err != nil {
+		log.Fatalf("failed to execute command: %v", err)
+	}
+}