fix(externals): keep both version of conflicting dependencies

[mahdiboomeri]

🔗 Linked issue

resolves #722
potentially resolves #612

❓ 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 keeps both versions of conflicting dependencies by nesting them inside their parent.
It also introduces a new nitro option called optimizeExternals which allows you to manually include or exclude specific packages to the optimization process.

📝 Checklist

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

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Name	Status	Preview	Updated
unjs-nitro	🔄 Building (Inspect)		Dec 23, 2022 at 10:50AM (UTC)

[itpropro]

Any feedback to this PR @pi0?

[codecov]

Codecov Report

Merging #758 (158675b) into main (0106bd1) will increase coverage by 0.30%.
The diff coverage is 91.48%.

@@            Coverage Diff             @@
##             main     #758      +/-   ##
==========================================
+ Coverage   70.07%   70.37%   +0.30%     
==========================================
  Files          57       57              
  Lines        5229     5377     +148     
  Branches      575      600      +25     
==========================================
+ Hits         3664     3784     +120     
- Misses       1556     1584      +28     
  Partials        9        9              

Impacted Files	Coverage Δ
src/utils/tree.ts	12.12% <0.00%> (ø)
src/build.ts	45.00% <50.00%> (ø)
src/rollup/plugins/externals.ts	90.14% <94.31%> (-4.17%)	⬇️
src/rollup/config.ts	91.60% <100.00%> (+0.01%)	⬆️
src/types/nitro.ts	100.00% <100.00%> (ø)

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[pi0]

Thanks legendary @mahdiboomeri for this implementation 💯

During the local review, I found that we could improve overall implementation and performances by using pre-resolved data structures for traced files and packages and then apply new strategy from this. I have moved the additions and explanation to ~> #782 before merging them together. Please feel free to try it and suggest or directly make PR in top of it if i missed something.

Cheers.