[!!!][TASK] Remove unused JS configuration options in Backend

There are a lot of unused JavaScript values set since TYPO3 4.x which
aren't in use anymore at all, and can be removed.

Releases: master
Resolves: #73719
Change-Id: I5dd86da26d6fa84ff13e0a82f446a6ded06f430c
Reviewed-on: https://review.typo3.org/46823


Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>