[TASK] Clean up gitlab-ci

* Acceptance tests in nightly run can use just one out of our
  supported databases, that should be enough.

* Some reorderings to reflect order in gitlab-ci better

* Minor issues and cleanups

Releases: master
Resolves: #93456
Change-Id: I67355f139e24ec9c287ab3b753059a342b387700
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/67660


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>