Relicense some files from lgpl2-only to lgpl2.1-or-later
This is the recommended license for frameworks and this fixes some minor license incompatibilities with other software.
@hallas you contributed to these files so it would be great if you could approve this MR
Additionally it would be great if you could add your name to https://invent.kde.org/sdk/kde-dev-scripts/-/blob/master/relicensecheck.pl?ref_type=heads with the license changes you agree with