[!!!][TASK] Harden \TYPO3\CMS\Extbase\Service\ImageService

- Use strict type mode
- Use type hints whereever possible

Releases: master
Resolves: #87599
Change-Id: I8840b7fad16c4fffb7f50973fb97a498e0f683e4
Reviewed-on: https://review.typo3.org/59594


Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
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>