Inline worker script for easier library usage

[eligrey]

We should inline our worker script so that the entry bundle can instantiate penumbra workers without any external URL references.

We can do this by adding a build step to compile the worker script and expose this through process.env (or similar) for embedding by Webpack. This embedded minified worker script could be allocated to a Blob URI at runtime and used for worker instantiation.

[michaelfarrell76]

potential solutions invole https://webpack.js.org/loaders/worker-loader/ or https://github.com/GoogleChromeLabs/comlink-loader

[eligrey]

This seems best solved with Module Blocks.