Support pprof format

[nicolastakashi]

It could be nice if mini profiler expose pprof format so that we can take advantage of tools such as parca

[NickCraver]

I'm afraid I don't have any time to look into this in the near future, but if someone wants to look in and contribute I'm happy to take on the package size, e.g. we could have a MiniProfiler.<something> package that lives in this repo to export to it from a MiniProfiler object (no reason it needs to be in the base package anyhow).

I'm curious how this differs from the Open Telemetry effort, which is also something I'd want to export to.