[CLEANUP] Add phpDoc to properties in ext:filelist

Resolves: #62758
Releases: master
Change-Id: I7ce07e74d8e65f77d535a0505c2175ee249cff81
Reviewed-on: http://review.typo3.org/33864
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>