improve dependency management

[Devon Rueckner]

Currently we have a situation where there is one top-level package.json file, and:

1. some dependencies used by the shared component library (/lib) are in dependencies
2. other dependencies used by the shared component library (/lib) are expected/assumed to be provided by the library user
3. all other design system dependencies are in devDependencies. This includes both build and run-time dependencies

This situation will be hard to maintain. Preferably, we want:

• Depending on the shared component library be fast and easy:
  • install only the dependencies needed in node_modules
  • support tree shaking in webpack
  • handle situation where dependencies may already be provided by the user (perhaps using peerDependencies?)
• When managing design system dependencies, we should be able to distinguish between run-time and build dependencies.
• While using sub-packages might be a good strategy, we've also encountered many developer ergonomics problems with both Lerna and yarn workspaces, so we should approach this strategy with caution