Extract more tags from exif metadata

Summary:
Extract more metadata from exif that can
be easily mapped to the available properties.
This includes description, copyright, software
and artist.

BUG: 341162

Reviewers: bruns, mgallien

Reviewed By: bruns

Subscribers: kde-frameworks-devel, Baloo

Tags: Frameworks, Baloo

Differential Revision: https://phabricator.kde.org/D16931