feat(nuxt): share asyncData between calls

[OhB00]

Had a look at nuxt/nuxt#13910 and #5078 and made some changes to improve readability, and fix the race condition mentioned in the issue.

I have also implemented the change suggested in the other pull request to share asyncData between calls.

🔗 Linked issue

nuxt/nuxt#13910

❓ 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

1. I have refactored useAsyncData to use more async await, this (hopefully) makes it much more readable + manageable.
2. I have eliminated some dead code from various code paths, _nuxtOnBeforeMountCbs are no longer touched at all server side, data caching is handled top level rather than within refresh,
3. refresh was simplified with the concept of 'tagging along', if a promise is found for a key, use that instead of calling the handler again.
4. asyncData is sync'd between calls, for example, if you had a useUserData composable, that displays user data in two separate components, calling refresh will change both.
5. As a result of the previous point various bugs related to no sync are resolved (#4758 and likely others)
6. Added a force option to refresh, this seems to make more sense then what was provided in the documentation originally, this may be a breaking change.
7. Added some tests for useAsyncData, as it's fairly easy to break.
8. Refreshing on the server side updates the cache, this seemed logical.

📝 Checklist

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

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[OhB00]

3rd times a charm

[antfu]

Please revert the formatting changes before we could proceed reviewing.

[OhB00]

Reverted formatting changes

[pi0]

Thanks for your nice PR @OhB00 and sorry it took long to proceed.

I have splitted your changes into smaller PR and issues (next times, please consider doing this. this way we can quickly iterate over smaller changes)

1. I prefer to avoid using await in this particular utility because we only have current component/nuxt context available until first await and this utility returns a hybrid promise interface
2. Merged via perf(nuxt): tree-shake asyncData client logic from server #7056
3. Iterating over with some refactors.
4. (main fix) Done via fix(nuxt): use shared state for asyncData #7055 -- probably needs iteration to handle edge cases like ones @danielroe mentioned in fix(nuxt): use shared state for asyncData #7055 (comment)
5. (same as 4)
6. Moved to discussion Force refresh for useAsyncData and useFetch nuxt#14746
7. Merged via fix(nuxt): use shared state for asyncData #7055
8. (same as 3)

Thanks again!