Various code and helpers around the removed
CSH feature.

Resolves: #101058
Related: #100963
Related: #97312
Releases: main
Change-Id: I9143aebb24e448b6904a4198555775abbb6d5b39
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/79372


Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>