doc: update package.json field definitions

Only imports has the experimental status right now but technically all
ESM related features are currently experimental. The list also doesn't
appear to be in any specific order so I've grouped the experimental
features together.

PR-URL: https://github.com/nodejs/node/pull/35741


Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Derek Lewis <DerekNonGeneric@inf.is>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Ujjwal Sharma <ryzokuken@disroot.org>