Update loglevel icons
Summary:
Some of these icons don't even exist in breeze, others are semantically wrong. This causes problems when porting away from using pixmaps.
I'm not 100% happy with the selection, but better than nothing I guess
Reviewers: Plasma, davidedmundson
Reviewed By: Plasma, davidedmundson
Differential Revision: https://phabricator.kde.org/D26347