[!!!][TASK] Harden \TYPO3\CMS\Extbase\DomainObject\DomainObjectInterface

- Use strict type mode
- Use type hints whereever possible

Releases: master
Resolves: #87608
Change-Id: I3fc153c68bb29aa85517965c6d4d8414d25af35b
Reviewed-on: https://review.typo3.org/59602


Reviewed-by: Mona Muzaffar <mona.muzaffar@gmx.de>
Tested-by: Mona Muzaffar <mona.muzaffar@gmx.de>
Tested-by: TYPO3com <noreply@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>