[TASK] Drop 'typo3/ should be link' recommendation

The recommendation of FolderStructure having index.php and typo3/
folder as links is old fashioned, even if not using composer
based instances. The config has no functional meaning in the
install tool and can just be dropped.

Change-Id: Ie8addd1713cadeb381a11cf9a362ac255da6e72c
Resolves: #83550
Releases: master
Reviewed-on: https://review.typo3.org/55343


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Tested-by: Jigal van Hemert <jigal.van.hemert@typo3.org>