PnP ESLint compatibility

[arcanis]

Summary

The subject has been covered in various other topics (eslint/eslint#10125 and derivates), but basically the way ESLint works doesn't allow react-scripts to cleanly provide its own lint plugins. Since it's an important use case I want to support, something has to be done.

This diff makes it so that react-scripts becomes a fallback of its own if found in the dependency tree (it still has a lower priority than the top-level fallback). Note that these fallbacks are not considered for files loaded from the top-level package (meaning that an application file doing require('foo') without listing foo in the top-level package.json will throw, even if react-scripts depends on foo). This ensures people won't accidentally rely on the fallback when developing their own applications.

Test plan

I explicitly don't want to test this, since it's a workaround and this kind of behavior should not be expected globally speaking.

[buildsize]

File name	Previous Size	New Size	Change
yarn-[version].noarch.rpm	1.07 MB	1.07 MB	211 bytes (0%)
yarn-[version].js	4.2 MB	4.2 MB	1.08 KB (0%)
yarn-legacy-[version].js	4.37 MB	4.37 MB	1.08 KB (0%)
yarn-v[version].tar.gz	1.07 MB	1.08 MB	1.66 KB (0%)
yarn_[version]all.deb	791.13 KB	791.41 KB	278 bytes (0%)