fix: use @docusaurus/react-loadable as package alias + include types

[slorber]

Motivation

Fix for @types/react-loadable depending on Webpack 4, creating conflicts for some users.

Fixes #5772

See also DefinitelyTyped/DefinitelyTyped#56726

Using npm package aliases permits to more easily remove hacky module-alias.

It seems supported by all major package managers for a long time: npm 9.6, yarn 1, pnpm...

so it looks like a good solution to use forked libs in both Webpack+Node.

This also allows other tools like eslint to understand this aliasing.

Have you read the Contributing Guidelines on pull requests?

yes

Test Plan

CI should pass

[netlify]

✔️ [V2]

🔨 Explore the source changes: e4bb188

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😎 Browse the preview: https://deploy-preview-5819--docusaurus-2.netlify.app

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	70
🟢 Accessibility	98
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-5819--docusaurus-2.netlify.app/

[github-actions]

Size Change: 0 B

Total Size: 847 kB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/globalData.json	38 kB
website/build/assets/css/styles.********.css	94 kB
website/build/assets/js/main.********.js	425 kB
website/build/blog/2017/12/14/introducing-docusaurus/index.html	68.2 kB
website/build/blog/index.html	39 kB
website/build/docs/index.html	46.1 kB
website/build/docs/installation/index.html	53.6 kB
website/build/index.html	31.6 kB
website/build/tests/docs/index.html	27.3 kB
website/build/tests/docs/standalone/index.html	23.8 kB

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