Add FictionBook 2 icons
Summary: FictionBook 2 icons from Okular (design by Vladimir Prohorenkov, my implementation).
Test Plan:
Reviewers: VDG, ngraham, ndavis
Reviewed By: VDG, ndavis
Subscribers: ndavis, ngraham, kde-frameworks-devel
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D23300