Potential fix for code scanning alert no. 8: Missing rate limiting

[KDust7]

Potential fix for https://github.com/NightProxy/Daylight/security/code-scanning/8

To fix the problem, we will introduce rate limiting to the Express application using the express-rate-limit package. This will help prevent denial-of-service attacks by limiting the number of requests a client can make within a specified time window.

1. Install the express-rate-limit package.
2. Import the express-rate-limit package in the index.js file.
3. Set up a rate limiter with appropriate configuration (e.g., maximum of 100 requests per 15 minutes).
4. Apply the rate limiter to all routes that serve files from the file system.

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