documentation not being updated

The documentation is not being build any more - both the sphinx and the doxygen build process fails. I could build the sphinx part locally on my machine. The doxygen part also worked although only after I fixed an issue with dune-website/public/header/index.html and dune-website/public/footer/index.html not being found (public didn't have a header/footer folder so added folders with empty index.html).

I added a 2.7 version of the dune-fem python tutorial so changed the sphinx settings but I don't know if that is the issue and there seems no reason why the doxygen part is also failing.

https://gitlab.dune-project.org/infrastructure/dune-website/pipelines/25267