[TASK] Move Changelog files into 11.3 for upcoming release

With the release of TYPO3 v11.3, Changelog documentation is no
longer expected in master, but in 11.3 folder.

Resolves: #94532
Releases: master
Change-Id: I04808715808e6ac66e8a032e2809fc1d4d44109c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/69807


Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>