Add support for node module loading

[wuman]

This is a feature request.

A major use case for v8worker might be to load a node.js module (which may itself require more node modules as dependencies) to perform work, and then return the result back to golang. It would make v8worker much more useful if it has node module loading built in.

[sethwklein]

A workaround is using a bundler (webpack, Browserify, Rollup, etc.)