- Use strict type mode
- Use type hints whereever possible

Releases: master
Resolves: #88604
Change-Id: Ie2641c04a7e97313c657152c14bcf5b15d9d6a74
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61110


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Jonas Eberle <flightvision@googlemail.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Jonas Eberle <flightvision@googlemail.com>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>