[core] Define rules to modularize packages in Next.js

[michaldudak]

From #35457 (comment)

we can scale this (modularizing the icons package) to all the MUI npm packages, beyond @mui/icons-material. It could be done with special rules, like in https://github.com/vercel/next.js/blob/261db496f7cf04b70f078a6eae0c8baf6fe5c238/packages/next/src/server/config.ts#L738. I didn't have time in vercel/next.js#51953 to do it right, there was an urgency to fix it before it was rolled from their canary release to stable. Then, the question is is the Next.js job to keep this up to date? Is there a similar opportunity with Vite, should we update the Vite example as well? At the end of the day, it's about improving the DX.

[oliviertassinari]

This option in Next.js is gone: https://nextjs.org/blog/next-13-5#optimized-package-imports.

Previously, we added support for modularizeImports, enabling you to configure how imports should resolve when using these libraries. In 13.5, we have superseeded this option with optimizePackageImports, which doesn't require you to specify the mapping of imports, but instead will automatically optimize imports for you.

vercel/next.js#54695 is a great example of how we should details our PR descriptions. It explains well what's going on, and the implications.

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We can remove it, e.g.

material-ui/examples/material-ui-nextjs-ts/next.config.js

Line 5 in 7ee636b

modularizeImports: {