[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/auth/validator.go

@@ -0,0 +1,8 @@
+package auth
+
+import "hash"
+
+// Validator is an interface that defines the Validate method.
+type Validator interface {
+	Validate(func() hash.Hash, any) error
+}