docx: Full re-write of the Concourse site using MkDocs

[kcbimonte]

BLUF

As a Concourse Contributor, I want to modernize the Concourse docs using MkDocs, so that I can lower the barrier of entry for contributing new information.

Task List

Current task list:

• Move all existing files to .old
• Create skeletons for all pages
• Create redirects for all pages
• Transfer all docs information over
• Transfer all blog information over
• Determine how to display schemas
• Determine how to create homepage
• Update CI to support mkdocs (could use mkdocs gh-deploy --force) for ease of use

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: kcbimonte / name: Kevin C. Bimonte (03169ff, 103d06b, 27e7dbf, 322b029, 4359747, 57ff054, 5dddd5a, 5f628b6, 70bd557, 7fd1196, 89002c6, 8f93a3b, a8134ec, c62a228, cdc5097, d558403)

[taylorsilva]

This just came across my feed: https://squidfunk.github.io/mkdocs-material/blog/2025/11/05/zensical/

Some interesting tidbits:

• Mkdocs is unmaintained (?). Last release is August 2024 and master branch has received very few commits. I did not notice this before.
• Material for MkDocs is now in maintenance mode and the team behind it started zensical as a successor to mkdocs

I don't think we should try switching to their thing now. I think making this jump, booklit to Mkdocs, is a good first step. Then we can possibly look at moving over to Zensical. They mention they're putting significant effort into the mkdocs -> zensical migration path.

[kcbimonte]

Yup, just saw that as well and was going to suggest a slight pause on this to see how this whole Zensical thing played out before going any further.