chore: add examples

[Barbapapazes]

🔗 Linked issue

❓ Type of change

• [x] 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• [ ] 🐞 Bug fix (a non-breaking change that fixes an issue)
• [x] 👌 Enhancement (improving an existing functionality like performance)
• [ ] ✨ New feature (a non-breaking change that adds functionality)
• [x] 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• [ ] ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This PR add examples. In order to help users to understand how to use UnJS packages, I'm adding examples into the repo.

In the end, these examples will also be used on the website. https://github.com/unjs/website/pull/235

📝 Checklist

• [ ] I have linked an issue or discussion.
• [x] I have updated the documentation accordingly.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (53937f5) to head (a52566a). Report is 7 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #370 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 7 7 Lines 629 629 Branches 65 65 ========================================= Hits 629 629 ```

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[danielroe]

I might move these into the playground in future (or maybe create an interactive playground for users)...

Let's stay in touch on this so I don't break the website examples 🙏