Merge apt 1.9.0 port
from https://github.com/julian-klode/libqapt/tree/apt-1.9.0
Reviewers: O3 libqapt & debconf-kde, apol, sitter
Reviewed By: O3 libqapt & debconf-kde, apol, sitter
Subscribers: sitter
Differential Revision: https://phabricator.kde.org/D21896