kcms: Port away from org.kde.kcm.ConfigModule

org.kde.kcm.ConfigModule doesn't exist anymore. Its replacement lives in
org.kde.kcmutils module now.

Note that the replacement has no "quickHelp" property, so it's been
removed. While on this, also drop "ConfigModule.buttons". It still
exists in the new ConfigModule but the default buttons should be fine.

src/kcms/decoration/package/contents/ui/main.qml

@@ -16,7 +16,6 @@ import org.kde.newstuff as NewStuff
 KCM.AbstractKCM {
     id: root
 
-    KCM.ConfigModule.quickHelp: i18n("This module lets you configure the window decorations.")
     title: kcm.name
 
     framedView: false

src/kcms/desktop/package/contents/ui/main.qml

@@ -14,8 +14,6 @@ import org.kde.kirigami 2.20 as Kirigami
 KCM.ScrollViewKCM {
     id: root
 
-    KCM.ConfigModule.quickHelp: i18n("This module lets you configure the navigation, number and layout of virtual desktops.")
-
     Connections {
         target: kcm.desktopsModel
 

src/kcms/virtualkeyboard/package/contents/ui/main.qml

@@ -13,7 +13,6 @@ import org.kde.kcm as KCM
 
 KCM.GridViewKCM {
     id: root
-    KCM.ConfigModule.quickHelp: i18n("This module lets you choose the virtual keyboard to use.")
 
     view.model: kcm.model
     view.currentIndex: kcm.model.inputMethodIndex(kcm.settings.inputMethod)

src/kcms/xwayland/package/contents/ui/main.qml

@@ -15,8 +15,6 @@ import org.kde.kquickcontrols
 
 KCM.SimpleKCM {
     id: root
-    KCM.ConfigModule.buttons: KCM.ConfigModule.Default | KCM.ConfigModule.Apply
-    KCM.ConfigModule.quickHelp: i18n("This module lets configure which keyboard events are forwarded to X11 apps regardless of their focus.")
     KCM.SettingStateBinding {
         configObject: kcm.settings
         settingName: "Xwayland"