Use ReadTheDocs

[abkfenris]

Currently we're using Github Pages for hosting and Netlify for PR previews. We keep having issues due to Netlify's Python environment, and it's lack of support for Conda making our packages fall out of sync.

ReadTheDocs now supports Conda/Mamba, so we could simplify our environment, and have the same service manage the build and PR previews.

I remember we had some discussion about RTD before, and I can't remember exactly why we didn't use them and instead built our own versioning scheme. Was it due to the advertising? We can opt it out of advertising by someone getting a membership, which I just tried for Xpublish.

To get our existing old sites, we would probably want to tag the desired commits, then use post_build customization to pull those in. The other place to customize might be to use single version mode.

xref: #237 @emiliom @ocefpaf

[ocefpaf]

Was it due to the advertising?

I don't think we discussed that. BTW, I don't have a strong opinion on it. I never saw the appeal of RTD docs b/c it used to be quite complicated to use conda with it. That seems to have changed so it may be a nice option now.

[emiliom]

I'm good with whatever you two recommend, be it RTD or status quo. As long as existing capabilities are preserved, and you do all the work 😜 . Otherwise, we could wait until after OHW23.