[TASK] Functional tests for persisting relations in Extbase

Add functional tests for persisting 1:M and M:M relations
in Extbase.
This patch adds blog_example as an fixture extension.

Resolves: #55786
Releases: 6.2
Change-Id: If90c854c9cb86fd45dcdbc14319a0a416e9447a0
Reviewed-on: https://review.typo3.org/27492
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Stefan Neufeind
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn
[TASK] Extend functional tests with creation of additional folders

Extends the functional tests with the possibility to create additional
folders inside the TYPO3 CMS test instance created within typo3temp.

Resolves: #56194
Releases: 6.2
Change-Id: I3271b3877fc953a2d876e56fc18af823d2e2a609
Reviewed-on: https://review.typo3.org/27779
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Bernhard Kraft
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring