feat(myTischtennis): integrate Playwright for CAPTCHA handling and enhance login form functionality

- Added Playwright as a dependency to handle CAPTCHA challenges during login attempts.
- Implemented a new endpoint to retrieve the login form from myTischtennis, parsing necessary fields for user input.
- Enhanced the login process to utilize Playwright for browser automation when CAPTCHA is required.
- Updated the MyTischtennisDialog component to support local login form submission instead of using an iframe.
- Refactored the MyTischtennisController to include proxy functionality for serving resources and handling login submissions.
- Improved error handling and user feedback during login attempts, ensuring a smoother user experience.

backend/server.js

@@ -70,6 +70,7 @@ app.use(cors({
 }));
 
 app.use(express.json());
+app.use(express.urlencoded({ extended: true }));
 
 // Request Logging Middleware - loggt alle API-Requests
 // Wichtig: userId wird später in authMiddleware gesetzt, aber Middleware funktioniert auch ohne