Mathematical formulas on WB

It should be possible to create edit mathematical formulas on WB.

JS library: https://www.mathjax.org/#samples

Input formats will be limited to *TeX for now

Missing items:
1) Following JS need to be bundled:

• jax/element/mml/optable/MathOperators.js?V=2.7.2 \iiint_V \mu(u,v,w) \,du\,dv\,dw
• jax/output/SVG/fonts/TeX/AMS/Regular/GeneralPunctuation.js?V=2.7.2 {{ y = f' ( x ) }}

2) 'Math formula' dialog is not closable