Attica: Convert license statements to SPDX markers
Summary:
Convert license statements to SPDX markers and
add license files.
Reviewers: cgiboudeaux
Reviewed By: cgiboudeaux
Subscribers: dfaure, cgiboudeaux, kde-frameworks-devel
Tags: Frameworks
Maniphest Tasks: T11550
Differential Revision: https://phabricator.kde.org/D27106