feat(nuxt): experimental server component islands

[danielroe]

🔗 Linked issue

• Implements: https://github.com/nuxt/framework/discussions/666

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This PR adds support for rendering individual components through a special GET request to /__nuxt_render (implementing RFC https://github.com/nuxt/framework/discussions/666).

In addition to providing the basis for server-only components (#5688) it can also provide a way to render individual components for future testing or devtools functionality.

Note that this only supports components that are already globally registered in the server.

If you encounter any issues with rendering async components in this way, please also see vuejs/core#6207.

📝 Checklist

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

[netlify]

✅ Deploy Preview for nuxt3-docs canceled.

Name	Link
🔨 Latest commit	2484081
🔍 Latest deploy log	https://app.netlify.com/sites/nuxt3-docs/deploys/636e472d26f7980008784de0

[danielroe]

@pi0 What's the status of this PR?

[pi0]

Update: This PR is really in a good state and is ready to be landed as an experimental feature. I've also worked on inlined styles to be working on production (7c66c41) and added experimental.componentIslands flag.

Landing this feature for 3.1.0 alongside .server components. (Landing for 3.0.0 is really hard since we plan release today sorry for delays).

[josueayala27]

🫶🏻🫶🏻🫶🏻 @danielroe