Allow apps to opt-in storing state date in separate file
Because it is opt-in the behavior of apps that use the config for more complex session management does not change.
Task: https://phabricator.kde.org/T12549
Alternative to !76 (closed)
Because it is opt-in the behavior of apps that use the config for more complex session management does not change.
Task: https://phabricator.kde.org/T12549
Alternative to !76 (closed)