HTTP Server Benchmarks

@dinosaure nginx is going to be hard to beat. But it is interesting that the scalability shape between OCaml and nginx is not that different. Nginx just has the advantage that its single core performance starts from a much higher point.

I'm assuming these are all HTTP/1.1 benchmarks? Unfortunately `wrk` and `wrk2` don't support http/2, but I found this tool that does: https://nghttp2.org/documentation/h2load-howto.html

h2load - HTTP/2 benchmarking tool - HOW-TO — nghttp2 1.69.0-DEV documentation

@edwintorok Yes, the main goal is to have an oracle :) And yes, it's only HTTP/1.1. httpcats has an implementation of h2, but it takes time to run benchmarks (at least, to establish a real test protocol).