Migrate eslint-plugin-design-tokens to monorepo

### **Description**

Migrate the repository [`[eslint-plugin-design-tokens](https://github.com/MetaMask/eslint-plugin-design-tokens)`](https://github.com/MetaMask/eslint-plugin-design-tokens) to the [`[metamask-design-system](https://github.com/MetaMask/metamask-design-system)`](https://github.com/MetaMask/metamask-design-system) monorepo.

### **Technical Details**

- Follow the [[package migration guide](https://github.com/MetaMask/metamask-design-system/blob/main/docs/package-migration-process-guide.md)](https://github.com/MetaMask/metamask-design-system/blob/main/docs/package-migration-process-guide.md).
- Transfer the codebase, ensuring that all existing functionality remains intact.
- Update the project structure to align with the monorepo's conventions and configurations.
- Verify compatibility with the monorepo's existing tooling (e.g., linting, testing, and CI/CD workflows).
- Ensure that all dependencies are compatible with the monorepo environment.
- Adjust the documentation to reflect the migration, including new import paths and usage instructions.

### **Acceptance Criteria**

- The `eslint-plugin-design-tokens` functionality is fully integrated into the `metamask-design-system` monorepo.
- Migration follows all steps outlined in the [[package migration guide](https://github.com/MetaMask/metamask-design-system/blob/main/docs/package-migration-process-guide.md)](https://github.com/MetaMask/metamask-design-system/blob/main/docs/package-migration-process-guide.md).
- All tests pass in the monorepo environment.
- Documentation is updated to reflect the migration.
- CI/CD workflows in the monorepo are configured to support the new package.
- No regressions or disruptions are introduced to either project.

### **References**

- [`eslint-plugin-design-tokens` repository](https://github.com/MetaMask/eslint-plugin-design-tokens)
- [`metamask-design-system` repository](https://github.com/MetaMask/metamask-design-system)
- [[Package migration guide](https://github.com/MetaMask/metamask-design-system/blob/main/docs/package-migration-process-guide.md)](https://github.com/MetaMask/metamask-design-system/blob/main/docs/package-migration-process-guide.md)
- Relevant Slack threads or internal documentation, if applicable.

Start with docs/package-migration-process-guide.md and compare the eslint-plugin-design-tokens repository with the metamask-design-system monorepo conventions. Follow the guide to transfer the package, then verify its existing functionality, dependencies, tests, linting, CI/CD configuration, import paths, and usage documentation in the monorepo. Done means the package is integrated without regressions and all tests pass.

Written by the indexing model from the issue text.