[docs] try out pydata-sphinx-theme?

hey folks! I end up coming to the docs a fair amount (though often not soon enough, usually). It would be lovely if the docs were a little bit nicer on the eyes... recently, I've been trending towards (and contributing to) [pydata-sphinx-theme](https://github.com/pandas-dev/pydata-sphinx-theme).

There are lots of knobs to turn, but with a little bit of hackery, it could be something like this:

- desktop
- 
- mobile
- 

Under the hood, it's all the same stuff, and so the search wouldn't be much better... might be worth just delegating out to a custom google/ddg, as the meeting minutes end up crushing everything.