Fix dependency on external LaTex installation

[bytinbit]

The collage in nobubo is made with pdflatex, which is called as a subprocess. This is neither easy to deploy nor user-friendly - currently, users must pre-install LaTex, which might not be available on all systems.
Aim: Use a Python library or another trick so that deployment is easier and usability too. It might be achieved by using https://pypi.org/project/PyLaTeX/ .