[!!!][TASK] Prepare for new minimum system requirements

System Requirements have been announced for TYPO3
v12 [1]: PHP 8.1 and higher, raised minimum DBMS
versions and removed mssql support.

The patch sets according PHP requirements in
the central composer.json files:

> composer config platform.php 8.1.1
> composer req php:"^8.1"
> composer req php:"^8.1" -d typo3/sysext/core --no-update

The patch adjusts the core main test suite to run
tests with PHP 8.1, ignoring older PHP releases,
drops mssql from the test suites and raises versions
of other DBMS in the test suite.

The option set of Build/Scripts/runTests.sh is
updated accordingly. phpstan needs a special
handling since it is not PHP 8.1 ready, yet: The
code scanner is still run using PHP 8.0 for now.

With the default charset being changed to utf8
in mysql, an acceptance tests becomes obsolete and
is substituted with an @todo comment to further
investigate if we could streamline the underlying
code in the install tool.

[1] https://typo3.org/article/new-system-requirements-for-upcoming-typo3-v12

Resolves: #96553
Releases: main
Change-Id: I34981523dffe6c650a1126c0002f3fa519e11c65
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73035


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