Docs: Add documentation

[JacobCoffee]

Summary

Similar to https://polyfactory.litestar.dev/, have documentation that has a nice UI for people to look at the benchmarks. A place we can point people to.

https://benchmarks.litestar.dev/ (maybe we have to rename this repo 🤷🏽 )

[provinzkraut]

Hm. That's not really the purpose of this repo and I'm not sure we want a subdomain just for the benchmarks. We have a section in the docs, which is where they belong in my opinion.