Enhancements: Updated Styling, DB Structure & React Router v6 Support

### Summary
- I completed the tutorial and made significant updates.
- Applied heavy CSS styling changes to improve UI/UX.
- Added a `photo` column in `db.json` to add some image on `BlogDetails.jsx`, it is a fixed image only for design.
- Upgraded `react-router-dom` to v6, which required syntax updates in routing.

### Proposed Changes
- Updated routing logic to align with React Router v6.
- Enhanced UI with additional CSS refinements.
- Modified `db.json` structure to support images for blog posts.

### Why These Changes?
- The styling improves the user experience.
- React Router v6 is the latest version, ensuring better support.
- Allowing images in `db.json` enhances blog content.
- For contributions too. This is my first issue and PR in GitHub :)

### Would You Consider a PR?
I have already made these changes in my forked repo.