Upgrade project to be built locally and with latest dependencies

[evenstensberg]

Hi! Thx for creating tikzjax, it works well. I'm facing some issues when the tex script node has errors, wasm will throw a runtime exception.

A nice thing, would be to be able to run this repository locally, so that's what I'm suggesting now. If you need help with upgrading dependencies to the latest node version along with a better source code, I'm willing to help.

Let me know what you think! :)

[benrbray]

@evenstensberg You may be interested in my fork (of a fork of a fork) of tikzjax, where I've created a Dockerfile that makes all the dependencies explicit.