Improve build pipeline

The current build pipeline relies on bash pre- and post-build operations. For one, this isn't a great experience on Windows which doesn't handle .sh scripts particularly well out of the box and for another, it hides a lot of what's happening across tests of build scripts and that's not great from a maintenance perspective.

I'd like to look at using different build tooling for this. I've personally favored Webpack in the past since it's flexible, straightforward and easily adopted, but as part of this work, I'll see if there are any other favored alternatives out there.