The moc process already rebuilds the plugin when the JSON file changes, consequently the additional parameter is not needed.
Task: https://phabricator.kde.org/T14649
This automatizes the generation of logging categories so a
kdeconnect-kde.categories is generated and installed to
/usr/share/qlogging-categories5/ so kdebugsettings can use it.
Also, sets the default logging level to Warning. So now the logs
of users won't be filled with debug messages but they can
modify the configuration easily with kdebugsettings.
