[BUGFIX] Folder structure honors file and folderCreateMask

The folder structure class construct takes care of permissions
of files and folders. The patch adds support for config values
fileCreateMask and folderCreateMask.

Resolves: #49715
Related: #49162
Releases: 6.2

Change-Id: I9f41ba7f038992ef77cf212229fca524e346431f
Reviewed-on: https://review.typo3.org/21971
Reviewed-by: Steffen Ritter
Tested-by: Steffen Ritter