kcms/options: port to KCModule methods
Remove code that duplicates functionality of KCModule.
Previously the various config items were not fully ported to using KCModule methods, and kept custom versions of isSaveNeeded and isDefault. When called from KWinOptions::updateUnmanagedState, these methods incorrectly reports that there are still changes to be saved. This patch set ports all configs in window behavior to methods provided by KCModule, solving the problem.
(cherry picked from commit faab23e9)