Publish documentation

[alexgarel]

### Tasks
- [ ] use mkdocs and material theme
- [ ] Use sphinx to create the API documentation in a specific folder
- [ ] Use [autodoc-pydantic](https://autodoc-pydantic.readthedocs.io/en/stable/index.html) with Sphinx to auto-generate configuration documentation
- [ ] Eventually generate OpenAPI documentation to have it published standalone (with redoc or rapidoc)
- [ ] Add a check in CI for documentation build
- [ ] Publish all docs to github pages

See other projects to re-use scripts that do that:

• off-server generate doc
• off-server build_mkdocs

[alexgarel]

@Kout95 this is a thing to do also.

I can take care of mkdocs part, because I did it a lot of times.

But if you are ok to handle the sphinx build, I would be glad :-) The most important part is to generate the documentation for the configuration because it enables centralizing precise documentation there.