[!!!][TASK] Remove RTE transformation ts_preserve and preserveTags option

The functionality can be completely built with allowTags and is
more flexible.

ts_preserve was only used in the "old" "content (default)" ts_transform
functionality, which was removed already.

Resolves: #72870
Releases: master
Change-Id: Ic4b8b9ce02c0f7672664c909be3e24955b17f873
Reviewed-on: https://review.typo3.org/46134


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>