Migrate to Docusaurus v3

[nonprofittechy]

• Remove implicit links with <url> style
• Escape {
• Fix crosslinks

• Point to patched version of pydoc-markdown to escape { in autogenerated docs

  fix #409

[nonprofittechy]

Sorry to interleave myself in here, but I noticed a couple things that may need to be changed.

For the ALKiln docs, we need to change all :::caution admonitions to :::warning admonitions.

Thanks for spotting, I can take that on as it's a quick search/replace.

For the docs_style_guide, do they have a new file we could copy? It might have other changes, like admonitions, that we're not capturing here.

Honestly, I don't think we should have our own copy of this file. It's not really a great thing for us to maintain. But deleting it didn't seem in scope for this PR.

Not sure how much trouble we want to go through, but in case folks are interested, there are instructions on how to use Playwright with Argos to do visual snapshot testing which might help with such transitions. If people were super excited about this, I could try to put some time aside to work on it.

I don't think this would be a good fit for our size team/documentation site size/mostly internal audience, but if you have independent interest in it, definitely OK!

[nonprofittechy]

Going to merge given the size and auto-build checking, but there may be some regressions. We have a lot of other cleanup to do already in production.