Move to scoped packages for fonts, and use woff2 format

[dpvc]

This PR moves to using WOFF2 formatted fonts, and moves the font npm packages into the @mathjax scope. I've already published the font packages in that scope. A later step before beta.8 is release will be to move mathjax-full into the scoped package as well, which will require additional changes, both to the fonts and to MathJax source (mathjax-full will need to be replaced by @mathjax/src, for example). That will be done in a separate PR later.

The fontURL and dynamicPrefix values in these files aren't actually used, as they are overridden by the fonts, which are subclasses of the FontData objects and provide their own value for these.

This PR also corrects the tsconfig files to point to mathjax-newcm rather than mathjax-modern, which were missed in the PR that swapped the default font.

[dpvc]

I forgot to say that you need to use the lab-woff2 branch in the MathJax-dev repository to test this. Do a ppm install first to get the new versions of the fonts.