[TASK] Streamline DomainObjectInterface and AbstractDomainObject

- Introduce type declarations
- Enhance type information for phpstan/psalm
- Use modern PHP syntax in some places
- Refactor redundancies

Releases: main
Resolves: #100120
Change-Id: Ia2a018c589b131980b09246ffd3730b322bddc1d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78073


Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>