Summary:
Also manage KCModule states (isSaveNeeded and isDefaults)

BUG: 405573

Test Plan:
* exec kcmshell5 kwintouchscreen
* In an edge, select action Present windows - All desktops, then apply
* close and reopen
* Should display action Present windows - All desktops in the previously selected edge.

* Do same test with Present windows - current desktop

Reviewers: #kwin, ervin, bport, meven, zzag

Reviewed By: #kwin, ervin, meven, zzag

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D27862