Validate test ADH json files

[alwinw]

• Fix depreciation warnings from pydantic 2.0
  • Replaced min_items and max_items with min_length and max_length
  • Replaced class-based config with ConfigDict
• Add minimum version requirement pydantic>=2.0
• Add entrypoint script for validating a json file

[eduardo-ocampo]

These are good changes we want to merge into the main branch. Please note that we moved some files around and created a process to create our documentation using Sphinx. Merge the main branch back into your branch and resolve any conflicts.

[alwinw]

Thanks @eduardo-ocampo! Sorry for missing your comment earlier. I've just merged in main and removed the example mkdocs setup I had. Please let me know if there's anything else :)