feat(nuxt): prefetch middleware/layouts + await layout loading

[atinux]

❓ Type of change

• [ ] 📖 Documentation (updates to the documentation or readme)
• [ ] 🐞 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)
• [ ] ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

Hooked into link:prefetch to prefetch the layouts and middleware :rocket:

• Without: https://nuxt3-no-prefetch.surge.sh
• With: https://nuxt3-prefetch.surge.sh

I also forced thge prefetching of layout on route navigation (not needed to depend on Suspense) like I did on Nuxt 2, this way we don't change the page until the layout if fully resolved.

Before (slow 3g):

https://user-images.githubusercontent.com/904724/213266458-6774d029-1e55-4e2d-9dd8-e72fbfd5ae26.mp4

After (slow 3g):

https://user-images.githubusercontent.com/904724/213266476-e2e5486d-9a67-4de5-a7d4-1f4c861200f7.mp4

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[Luffyyy]

I don't know if it's related, but this looks similar https://github.com/nuxt/nuxt.js/issues/14860 just with nested routes instead of layouts and it's been like this for a while. Could you check if this pull fixes it or address it in general?

[danielroe]

Testing on edge would be very welcome @Luffyyy 🙏