Feature: Type definition file with dependencies

[mizdra]

• Make external tokens referenced in import statements.
• This allows us to understand the dependencies of CSS Modules files simply by parsing the type definition file.
• This is an important milestone for implementing stylelint rules to detect unused css rulesets in TypeScript code !! :exploding_head:

[mizdra]

solved by https://github.com/mizdra/happy-css-modules/pull/121