[Beta 1] Sass Modules

[joshblack]

Acceptance criteria

• A team must be able to @use a module from @carbon/styles or @carbon/react
  • A team must be able to bring in all styles
  • A team must be able to bring in specific component styles
  • A team must be able to configure the theme
  • A team must be able to use the design tokens from the package

Note: make sure it's obvious where the tests for this should live

Checklist

• Write Public API test for @carbon/styles for package exports #9168
• Write initial usage docs for @carbon/styles #9169
• Sass Module Refactor #8899
• Add all public API re-exports to @carbon/react #9173

Questions

• What is the integration strategy for IBM Plex in @carbon/styles?
  • In a beta release, would be great to move to stable soon but not a blocker for beta 1
  • Metrics of Variable Font is off compared to non-variable font files (not production ready)