[TASK] Cleanup ReferenceElementWizardController

Change-Id: I54107f14310be837aa6c7e1fa36248ab6117b6e3
Reviewed-on: https://review.typo3.org/31304
Reviewed-by: Alexander Schnitzler
Tested-by: Alexander Schnitzler
[TASK] Cleanup UnusedContentElementComand

Releases: 2.0.0
Change-Id: Ib89d64ae1215284780103a6b9ee3c965db2498b1
Reviewed-on: https://review.typo3.org/30966
Reviewed-by: Alexander Schnitzler
Tested-by: Alexander Schnitzler
Test scrutinizer without composer.json