[TASK] TYPO3 Coding Guidelines - Underscores are not allowed in the variablenames

Change-Id: Iea7fba8c6ffb61f43c0aea5bcf7670ee80306897
Resolves: #54685
Reviewed-on: https://review.typo3.org/26609
Reviewed-by: Alex Kellner
Tested-by: Alex Kellner