Fix code scanning alert no. 8: Missing rate limiting

[wagmarcel]

Fixes https://github.com/IndustryFusion/DigitalTwin/security/code-scanning/8

To fix the problem, we need to introduce rate limiting to the Express application. The best way to do this is by using the express-rate-limit package, which allows us to easily set up rate limiting for our routes. We will configure a rate limiter to limit the number of requests to the /auth endpoint to a reasonable number per minute. This will help protect the application from denial-of-service attacks.

We will need to:

1. Install the express-rate-limit package.
2. Import the express-rate-limit package in the KafkaBridge/lib/authService/index.js file.
3. Set up a rate limiter with appropriate configuration.
4. Apply the rate limiter to the /auth route.

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