Scalable FPS

[AdrianSosic]

Making our FPSRecommender more scalable or providing a similar scalable algorithm would be a nice improvement. Also tagging @myrazma here, who recently hit its limits.

There seems to be already a package for it. We might want to test it and consider it as optional dependency if it turns out to be useful for our problem: https://github.com/leonardodalinky/fpsample