[DOCS] Making the Open In Colab and Open in GitHub buttons part of the template, automatically generated

[ignacioct]

The idea is to set up the Open In Colab and Open GitHub Source as a template overridden feature of the mkdocs template, that should be possible. We have some context on how it was done in Argilla (readthedocs)

We've set that up automatically here for templating using nbsphinx docs: https://github.com/argilla-io/argilla/blob/0b91c8ff010d17e269c1969fdfe882449865af94/docs/_source/conf.py#L217

I assume it is possible with MkDocs too but the information seems lacking so don't spend too much time trying to reproduce it if you don't have a clear idea. https://www.mkdocs.org/user-guide/customizing-your-theme/#overriding-template-blocks