security: address code scanning alert for missing rate limiting

[kylejb]

Fixes https://github.com/kylejb/space-station-tracker/security/code-scanning/4

To fix the problem, we will introduce a rate-limiting middleware using the express-rate-limit package. This middleware will limit the number of requests that can be made to the server within a specified time window. We will apply this middleware to the entire application to ensure that all routes, including the one serving the file, are protected.

1. Install the express-rate-limit package.
2. Import the express-rate-limit package in the server.ts file.
3. Set up the rate limiter with appropriate configuration (e.g., maximum of 100 requests per 15 minutes).
4. Apply the rate limiter middleware to the Express application.

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[kylejb]

Branch renamed to: security/4-missing-rate-limit