DO NOT MERGE! Versioned Documentation on the website

[espy]

Overview

Important

Ahoi! ✋ This PR only contains the technical implementation, there is additional editorial work to do. Since we do not want to deploy just the tech bit, this PR should not be merged until the versioned pages have been revised. More info below.

This website PR allows us to publish versioned docs, like CouchDB does too. This means that the following parts of the website can change depending on the selected PouchDB version, and have a version switcher in the bottom right so users can directly switch between, say, the sync docs for 8.0.0 and the sync docs for 9.0.0 with a single click:

• Guides
• API
• Learn

Screenshots at the end of this PR.

The setup is:

• one folder per published version, with the aforementioned bits of the site in each of them, plus a folder for latest. Each of these contain Guides, API and Learn, and their respective sidebar navs, where applicable.
• a central docs/_data/site.js file that defines the available versions and which one of them is stable
• The URLs we all know and love from the existing site still work and always point to stable
• Any changes that are made to the current docs are to be made in the latest folder, and when the next release is made, that folder is duplicated and renamed to whatever that release’s version is.

Navigation:

• The top nav always points to stable.
• Once you switch into a different version, all other nav elements, e.g. the sidebar and the end-of-page prev and next buttons, stay within that selected version.
• There’s a sticky warning at the top of all non-stable versioned pages that the user is currently looking at out-of-date docs.

The PR also adds a WEBSITE_README.md to provide more details on the workflow and the 11ty setup used to make this possible.

Testing recommendations

Run locally with npm run build-site and test all the nav items. I've explicitly not gone over the links in the text on the versioned pages, since we’ll probably want to edit those.

Warning

If the site doesn’t build after checking out this branch, delete your build folder at /docs/_site and try again

Remaining editorial work

I’ve currently set this up to have versioned docs for 7.3.0, 8.0.0 and 9.0.0. 8.0.0 is when we added purge and activeTasks, and 9.0.0 was just generally a lot of changes. I see 7.3.0 as a historical starting point we could just mostly leave as-is, and the other two as worth updating. We could also opt to not bother with any of this, just start at 9.0.0 and pretend the past never happened.

If we do proceed with these three versions, we need to:

• Make sure that all text (non-nav) URLs within the 7.3.0 section work: the internal ones should point to the respective 7.3.0 pages, and all external links should be reviewed to see whether their targets still exist. Some of these are over a decade old. I've already made sure this version does not have docs for purge or activeTasks, but made no other content changes.
•  Update the 8.0.0 pages’ content through the board, including external references, plugin info, compatibility info, about pages, guides, which tutorial videos we link to/embed… all of it.
• Then use the updated 8.0.0 pages as the basis for the 9.0.0 pages.

For this work, I suggest making PRs against this branch.

Related Issues or Pull Requests

This is the final puzzle piece for #9246

Checklist

• I am not a bot
• This is my own work, I did not use AI, LLM's or similar technology for code or docs generation
• Code is written and works correctly
• Documentation changes were made in the docs folder