Add BlogPostCard component

[nukeop]

Introduces the BlogPostCard component to the library, designed specifically for showcasing blog posts.

• Component Addition: Adds the BlogPostCard component with props for href, thumbnail, title, excerpt, author, and date, enabling users to display blog post previews effectively.
• Styling: Includes styles.module.scss for the BlogPostCard, ensuring a visually appealing layout that is consistent with the design language of the library.
• Documentation and Examples: Updates README.md to document the BlogPostCard component, providing a usage example and describing its props for easy integration by users.
• Export Update: Modifies src/index.tsx to export the BlogPostCard, making it available for import and use in projects.
• Storybook Stories: Adds Storybook stories for the BlogPostCard in src/stories/BlogPostCard.stories.tsx, showcasing the default usage and a variant with a custom thumbnail, aiding in visual testing and documentation.
• Testing: Implements snapshot tests in src/__tests__/BlogPostCard.test.tsx to ensure the component's render output remains consistent over time.

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