feat(service): add auth menu and order service templates

src/main/java/dev/service/AuthService.java

@@ -0,0 +1,23 @@
+package dev.service;
+
+import dev.model.User;
+
+public class AuthService {
+
+    public boolean register(String username, String password, String email) {
+
+        // TODO:
+        // Validate and register user
+
+        return false;
+    }
+
+    public User login(String username, String password) {
+
+        // TODO:
+        // Authenticate user
+
+        return null;
+    }
+
+}