Message box methods: add API using "action" terms instead of "Yes" & "No" (and port from related KWidgetsAddons deprecations)
Needs kwidgetsaddons!151 (merged) see also discussion there for motivation.
Manually tested mainly with a special KIO worker to trigger all the message types, proposed for inclusion now in !994 (merged)
Edited by Friedrich W. H. Kossebau