UPGRADE/BREAKING: PyData v0.13 and HTML refactoring

[choldgraf]

This brings in several more updates for the PyData theme 0.13. It also adds support for several features that folks have requested.

• Adds two more buttons to our header buttons (theme and search). This is starting to get cluttered and we may want to move some stuff to the sidebar, but for now I'm just adding to this list so that we don't clutter up this PR too much.
• We now support dark mode! closes Add a dark mode #265
• We now use the "search icon" for searching, same as the pydata theme
• I fixed up a few CSS rules that were producing wonky behavior.
  • closes Clicking on right sidebar entry highlights wrong item #678
  • closes Long project names/titles no longer wrap in left navigation (version 0.4.0rc1) #681
  • closes Unable to set footer.html template #638
  • closes space wrongly added near <sub></sub> in sidebar #625
  • closes contributing link #619
  • closes Unable to customize footer and header  #565
  • closes Broken format when upgrading sphinx version #563
  • closes Allow for header customization #182
  • closes Make the topbar configurable with the PyData theme topbar code #334
  • closes Bootstrap 5 #332
  • closes Request for a feature to set the logo URL  #325
  • closes Set "readthedocs" ad placement explicitly #169
  • closes Cells do not shrink when some sidebar content overlaps with them #248

That's pretty much it so far! @mmcky or @AakashGfude can you find anything else we need to change?

To do

• Unpin the pydata theme to the latest release when v0.13 is out

[choldgraf]

Alright I've pinned us to the next pydata pre-release, so this should let us pull from PyPI. I've also made several updates to the theme based on the latest changes in PyData, and re-worked the documentation a bit to be easier to parse.

I think that this PR is too gigantic to be reviewed piece by piece, so I suggest that we merge it and focus on making iterative improvements moving forward.

Let's see how the tests go, and if they pass I intend to merge this and then cut a pre-release once @AakashGfude fixes up #584 . Then we can have another testing phase for people to provide feedback before a full release (and in the meantime, I think pydata will make a new version release too).

@AakashGfude this will also un-break the tests so that you can test out the PyPI fix without having the extra broken tests noise.

[choldgraf]

OK tests are happy, so I'll merge this one and update your branch @AakashGfude

[consideRatio]

Wieeeeeee!!! Amazing work! Super excited to see soo many issues resolve :)

I thought all these notifications of closed issues maybe was a mistake as they closed the very same minute, but wow - its because of this PR! I've never seen a PR resolve soo many issues in one go!! @choldgraf you hold the record now :D

🥇 🎉 🌻 ❤️

[choldgraf]

Haha to be fair many of these were inherited from the pydata theme, which has had a lot of work from many people over the months

[James11222]

Sorry I'm a little bit of a Github novice and don't really know how all of this works. So does this mean I can now toggle dark mode in Jupyter books? Or is there still a little bit of time we have to wait for a new version on the website or something?

[choldgraf]

It will be possible soon! We must first "make a release of this theme", and then in Jupyter book we must update the version and then make a release there too. Then it'll be available for jupyter book users 👍