[CLI] cli command for design files

[mauroerta]

Merge design files in the main theme

I think it could be useful in terms of developer experience to write the style of the components close to the component it self, for example:

-- src
-- -- components
-- -- -- MyComponent
-- -- -- -- MyComponent.tsx
-- -- -- -- MyComponent.morfeo.ts
-- -- -- -- index.ts

The content of MyComponent.morfeo.ts can be something like:

export default {
  tag: 'button',
  style: {
    bg: "primary",
    borderRadius: "m",
    px: "l",
   // ...
  },
  variants: {
    // ...
  },
}

Then, by running something like:

morfeo build-theme

The CLI will find all the {componentName}.morfeo.ts files and merge in the main theme:

// theme.ts
export default {
  colors: {....},
  spacings: {....},
  // ...
  components: {
    [componentName]: {
       // ... content from {componentName}.morfeo.ts
    }
  },
}