Warn user before copy/move job if the file size exceeds the maximum possible...

Warn user before copy/move job if the file size exceeds the maximum possible file size in FAT32 filesystem(4 GB)

Summary: BUG: 198772

Test Plan:
1. Prepare copy/move job.
2. Copy/move the contents to external USB drive/ Pen drive formatted with FAT32

Result: Inline error message appears.

Reviewers: ngraham, #frameworks, bruns, dfaure

Reviewed By: ngraham, bruns, dfaure

Subscribers: davidedmundson, elvisangelaccio, dfaure, cfeck, bruns, kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D16249