[!!!][TASK] Streamline Extbase validators

This follows the preparations of #96332 which has
been applied to v11 and v12.

The Extbase validator interfaces are streamlined
and more strict, setOptions() is now mandatory.

All validators now declace strict_types=1 and
all non-abstract validators are declared final.

A ReST file of the breaking interface and
AbstractValidator signature changes explains
details on how to stay compatible with v11 & v12
aware extensions.

Since a lot of the existing unit tests mock
single validator subjects, which is no longer
possible when they're final, those tests are
transferred to functional tests.

Change-Id: If04a04e78e2539017da00ae1607cad1c8615774f
Resolves: #96998
Related: #96332
Releases: main
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73644


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Benni Mack <benni@typo3.org>