Add rate limiting

[Floppy]

Various things would benefit from rate limiting to avoid DoS, spam, or just overloading by one user at the expense of others. There must be a general rate-limit system we can look into that will do this.

Need to limit:

• [ ] Upload frequency and size for #2236
• [ ] Login attempts #2238

[Floppy]

This is coming out of the box in Rails 8! https://www.bigbinary.com/blog/rails-8-rate-limiting-api

[Floppy]

https://github.com/rack/rack-attack?tab=readme-ov-file is also relevant