Docs: infer navigation hierarchy from filesystem

[ozkatz]

Context: The docs are due for a restructuring - meaning moving around a lot of pages. to make it easier, this PR removes just-the-docs' need to specify a parent and grand_parent to every item and setting has_children on every parent.

It's not the prettiest code (thank you Liquid, and bigger thank you to GitHub Pages for not allowing custom Jekyll plugins).

Once the restructuring is complete, I'm OK with going back to the standard just-the-docs method if we don't want to maintain this.

[github-actions]

♻️ PR Preview 15cad63 has been successfully destroyed since this PR has been closed.

_{🤖 By surge-preview}

[ozkatz]

one regression this introduces that I'm not sure is worth fixing now (assuming we revert this at some point) is that breadcrumbs are gone :(

[nopcoder]

@ozkatz we no longer bound to github pages. you can use any plugin or version of site generator you like, we build the site and push it to the docs repository. we use github pages to render the static generated data.

[ozkatz]

@nopcoder ahhhh nice! Does that mean I don't even have to use Jekyll? 🫣

[nopcoder]

@ozkatz yes, it should work. need to update the workflow with the tool you pick.
if you like to experiment, you can trigger the workflow on commit, just make sure you do not override the root. we usually publish to the /vXX.XX and /.

[nopcoder]

Some of the navigation items doesn't work - https://treeverse-lakefs-preview-pr-9151.surge.sh/experimental/