add helper functions defineConfig and definePlugin

[odanado]

Libraries such as Vite and Nuxt provide functions to support Config and plugin definitions.

• Vite defineConfig
• Nuxt defineNuxtPlugin

These helper functions provide the developer with IDE's intellisense through type definitions and jsdoc.

The developer will see less documentation when writing the configuration, reducing typos and other errors.

I am interested in implementing these helper functions. May I create a pull request?

[break-stuff]

@odanado I would love to see this PR and would be happy to review it!