feat: Setup docs scaffolding

[edeandrea]

Set up the Antora scaffolding. Quarkus has a really nice Antora extension we can use if we'd like (https://docs.quarkiverse.io/quarkus-antora/dev/index.html).

It should be themed to match the rest of the Docling projects.

Depends on #4

[edeandrea]

@ThomasVitale / @lordofthejars do either of you have any issues if we use mkdocs instead? Thats what the main docling site uses and it'll be much easier to just copy the site design rather than creating an Antora version of it.

[lordofthejars]

Yes, go head.

[ThomasVitale]

@edeandrea does mkdocs support versioning? If not, do we want to offer the possibility to check the documentation for a specific release of Docling Java?

[edeandrea]

It does support versioning: https://github.com/mkdocs-material/example-versioning

[ThomasVitale]

Nice! I didn't see any versioning on the Docling docs website, but if it's supported by mkdocs then we can configure it for Docling Java