eslint: Add eslint-plugin-package-json (#44559)

This eslint plugin will sort package.json files and apply other
cleanups, replacing the manual use of `sort-package-json` which we're
currently only applying to the monorepo root file.

The configuration is slightly complex, in that we want different
treatment for files in different places:
* Only js-packages require a `name` field.
* Only public js-packages require a description or version.

Author: anomiex

package.json

@@ -36,11 +36,11 @@
 		"jetpack-js-tools": "workspace:*",
 		"stylelint": "16.19.1"
 	},
+	"packageManager": "pnpm@10.4.0",
 	"engines": {
 		"node": "^22.12.0",
 		"pnpm": "^10.4.0"
 	},
-	"packageManager": "pnpm@10.4.0",
 	"pnpm": {
 		"patchedDependencies": {
 			"@wordpress/dataviews": ".pnpm-patches/@wordpress__dataviews@4.12.0.patch"