[Logout] Port to QQC2 and PC3

The logout screen is ported to QtQuick Controls 2 and Plasma Components 3.

lookandfeel/contents/logout/Logout.qml

@@ -19,10 +19,10 @@
 
 import QtQuick 2.2
 import QtQuick.Layouts 1.2
-import QtQuick.Controls 1.1 as Controls
+import QtQuick.Controls 2.12 as QQC2
 
 import org.kde.plasma.core 2.0 as PlasmaCore
-import org.kde.plasma.components 2.0 as PlasmaComponents
+import org.kde.plasma.components 3.0 as PlasmaComponents
 import org.kde.kcoreaddons 1.0 as KCoreAddons
 
 import "../components"
@@ -77,7 +77,7 @@ PlasmaCore.ColorScope {
         includeUnusedSessions: false
     }
 
-    Controls.Action {
+    QQC2.Action {
         onTriggered: root.cancelRequested()
         shortcut: "Escape"
     }