Webpack, potrace, upgraded internals

Brings a major upgrade to the inner workings of the core, as well as other packages.
This has been in the works for a while to support new forms of integration, such as the new webpack loader!

🚨 While many aspects remain the same, this may introduce some slight breaking changes 🚨

✨ Added

• Webpack loader (@ipp/webpack)
• Potrace pipe (@ipp/trace)
• Repository tests (package.json sync)

🛠 Changed

• Better internals for the core
• Better common types
• New async unbuffered flow for CLI
• Better config and manifest formats
• General improvements
• Readme, new homepage and in-house documentation

🗑 Removed

• The broker (@ipp/broker), replaced by a better thread-elevation script