display.notebook_repr_html -> display.html.notebook

[jreback]

reorg on the html options, which I think we are going to need some more e.g. df.style.

This will make it more consistent with the option config style

need to deprecate the original and add new.

[jreback]

anyone want to do this one?

[TomAugspurger]

@rdk1024 do you have time / interest to do this? It'll be similar to your work in #16970

We're doing a release candidate near the end of the week.