feat: add `dragonfly` driver

[oritwoen]

trafficstars

🔗 Linked issue

Close #294

❓ Type of change

• [ ] 📖 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)
• [ ] 🧹 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 adds information about dragonfly in the documentation and an additional export for better DX.

📝 Checklist

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

[nuxt-studio[bot]]

✅ Live Preview ready!

Name	Edit	Preview	Latest Commit
unstorage	Edit on Studio ↗︎	View Live Preview	a170f67c8ddc9ab968006fea252f3efe7aef71e2

[drewbitt]

Are there any remaining changes requested?