Add role for file creation time.

Summary: At least on FreeBSD UFS and ZFS support birthtimes of files.

Reviewers: FreeBSD, Dolphin

Subscribers: Konqueror

Differential Revision: https://phabricator.kde.org/D6243

(cherry picked from commit d8061b4d9e04ec940ee33feae5f60f26bffc97b1)