TYPO3 Core

Dear Core Team,

I think we could benefit from using Flysystem (https://packagist.org/packages/league/flysystem) under-the-hood. It has more than half a BILLION downloads on packagist.

1. Use flysystem with a custom LocalTypo3FileSystem

- This could replace all explicit calls to GeneralUtility::writeFile, GeneralUtility::mkdir_deep, GeneralUtility::fixPermissions.
- We could ensure that lockRootPath etc. is contained
- We might actually create wrappers to EXT:
- There are "Path Prefix" and "PublicUrlGenerator" solutions to overcome certain specialities which we had in the past

2. Use flysystem as default "LocalDriver" in FAL

- This would allow us to make custom drivers easier because we could allow to use other flysystem adapters in FAL
and make our API drastically smaller

There is an older version POC: https://github.com/cedricziel/fal-flysystem