[TASK] gitlab-ci: PHP 8.0 functional nightlies with mariadb 10.5

Next to pre-merge test suite, nightlies now especially run
the composer min/max functionals with PHP8. Using mariadb
10.5 to cover another DBMS variant.

Needs a friendsoftypo3/phpstan-typo3 raise:
composer require --dev friendsoftypo3/phpstan-typo3:^0.7.0

Change-Id: Iea86496e32a586b20d4d6eeb6db84ec5a06d0767
Resolves: #94061
Releases: master
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68991


Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>