feat: add export format "Amazon Style Dictionary"

[TimKolberger]

Feature request

📝 Description

We maintain a separate design system with our own component library, and want to migrate to the new DB X tokens.
Our token management is based on Amazon Style Dictionary with our core tokens, semantic tokens and component tokens.

🧑‍🏫 Problem Statement

The Theme Builder export does not contain a .json export for the core and semantic tokens which are compatible with Style Dictionary.
The other exports (CSS, Android, Utils, or WhiteLabelTheme.json) are not compatible.

🧑‍🔬 Possible Solution

The Builder could export additional files in the Style Dictionary format:

.
├── StyleDictionary
│   └── core-tokens
│           ├── colors.json
│           ├── sizes.json
│           └── ...
│   ├──  semantic-tokens
│           ├── colors.json
│           └── colors-dark.json

Where the core-tokens/colors.json could look like this:

{
  "colors": {
    "blue": {
      "50": {
        "value": "#EFF7FD"
      },
      "100": {
        "value": "#e0effb"
      }
      // ...
  }
}

core-tokens/sizes.json:

{
  "sizes": {
    "1": {
      "value": "0.25rem"
    },
    "2": {
      "value": "0.5rem"
    }
    // ...
}

semantic-tokens/colors.json:

{
  "colors": {
    "brand": {
        "value": "{colors.red.500.value}" // variable references
      }
    // ...
  }
}

semantic-tokens/colors-dark.json:

{
  "colors": {
    "brand": {
      "_dark": {
        "value": "{colors.red.400.value}"
      }
    }
  }
}

📝 Additional Information

We use Style Dictionary to generate theme definitions for tailwind, Chakra UI, Vanilla Extract and plain CSS.
These new export formats would help us to align with the DB X Design System mid to long term.