Migrate away from `mdx` stories to `CSF` format

[brionmario]

Is your suggestion related to an experience? Please describe.

We are currently using Storybook v6, which supports stories written in both mdx and CSF formats. However, with our planned migration to Storybook v8 (see issue #52), it is recommended to move away from the mdx format and standardize on the CSF format for better compatibility with the new version and improved scalability.

Describe the improvement

• Migrate all existing mdx stories to CSF format to align with Storybook v8 requirements.
• CSF is more compatible with Storybook v8 and offers better integration with advanced features like dynamic rendering, story controls, and addon management.
• This migration will enhance the maintainability of the codebase and streamline future upgrades or enhancements.
• CSF simplifies the separation of components and narratives, making it easier for developers to create, modify, and manage stories as the library grows.

Additional context

• Migrating to CSF will prepare us for the transition to Storybook v8.
• Storybook v8 has dropped some mdx features in favor of CSF for better support of the latest tooling and community standards.
• You can refer to the Storybook v8 migration guide and the CSF documentation for conversion guidelines.