docs: unify all the docs pages on the site

[MrPowers]

The docs pages are versioned and here is the landing page:

Here's what the programming guides page looks like:

This programming guides page includes SedonaSpark, SedonaFlink, and SedonaSnow - these all use the same version.

The SedonaDB docs have different versioning and a different horizontal navigation bar:

The SpatialBench docs aren't versioned but also have a different horizontal navigation bar:

How can we unify all these pages to flow as a single, coherent site? Some requirements:

1. all existing URLs should continue working, but redirects are possible
2. API docs should be versioned
3. We should probably remove versioning from other pages, like the blog

Feel free to add your thoughts on how to accomplish this best!