Refactor project structure to improve developer experience

[ttoino]

The current developer experience is pretty awful, there are no automatic checks like linters or formatters, installing and testing the extension is manual, and we have to use vanilla js and css for everything. To remedy this, several steps have been outlined and should be followed:

• Migrate the build step to a better system #164
• Add typescript support #166
• Add support for CSS nesting #167
• Add support for JSX/TSX so we don't have to use the default DOM bindings
• Add a linter and formatter #20
• Add a feature system to reduce boiler plate code and potential incompatibilities
• Automate code checking with github actions
• Fully migrate all existing code to the new systems