This change aims to reduce the amount of inline JavaScript by
removing `onchange` events.

* extracts inline JavaScript from templates
* introduces `TYPO3/CMS/Backend/GlobalEventHandler` module
* adjusts PHP type-hints to their correct & actual values

Resolves: #91052
Releases: master
Change-Id: If92391bd48f89df57fbb0ed6f8b0936da0e1a49d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/64191


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>