Upgrade Mathjax to version 3

[benabel]

Mathjax 3 is stable since september 2019, https://github.com/mathjax/MathJax/tree/3.0.0, are you planning to allow this renderer or this should be done by manually configuring the H5P.MathDisplay.rendrerer config.

[pjotrsavitski]

@benabel Have you tried updating it manually and did it work as expected?

[benabel]

@pjotrsavitski No I was waiting for an answer of the mainteners. I've moved to simpler web-component approach for my quizzes.