Try using tectonic instead of texlive directly

[tomhoule]

This was just announced:

https://github.com/tectonic-typesetting/tectonic

We could use it as a library. Awesome.

[tomhoule]

Tectonic looks like it is still actively being developed, which is good, but since we use the debian stable version of texlive in the image now, it doesn't seem as urgent.