[TASK] Migrate more test fixtures to CSV

* Migrate most test fixtures from .xml to .csv.
  Some special cases are left out, those will
  receive dedicated patches.
* Streamline assertCSVDataSet() and
  importCSVDataSet() usage to __DIR__
  relative paths.

Resolves: #96856
Releases: main, 11.5
Change-Id: I747aafa03c031aa655c8f2a9ab71027ee2accddc
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73454


Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Susanne Moog <look@susi.dev>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>