[TASK] CGL Cleanup of ResourceStorage

To ease further backporting this change
backports some non functional CGL cleanup
to 6.0 branch

Releases: 6.0

Change-Id: Idf9d728a9143ab5cec311401fb6f56220c1f58a4
Reviewed-on: https://review.typo3.org/23556
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel