Added the actual Contao 3 Files implementation candidate (see #5307)
Make the `File` class behave backwards compatbile (see #5307)
Revert Make the `File` class behave backwards compatbile (see #5307)
Add the `$blnDoNotCreate` flag
Adjust the core files to trigger the new `$blnDoNotCreate` option
Added a log entry
Merge branch 'hotfix/file-tmp-first' into hotfix/3.0.4