Port kwin from Plasma Components2

Testing done:
 - ran present windows, checked the button
 - changed desktop with the OSD enabled
 - toggled nightcolour (which shows the other OSD)

src/effects/presentwindows/main.qml

@@ -7,11 +7,11 @@
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 import QtQuick 2.0
-import org.kde.plasma.components 2.0 as Plasma
+import org.kde.plasma.components 3.0 as Plasma
 
 Plasma.Button {
     id: closeButton
-    iconSource: "window-close"
+    icon.name: "window-close"
     anchors.fill: parent
     implicitWidth: units.iconSizes.medium
     implicitHeight: implicitWidth

src/qml/onscreennotification/plasma/main.qml

@@ -8,7 +8,7 @@
 import QtQuick 2.0;
 import QtQuick.Window 2.0;
 import org.kde.plasma.core 2.0 as PlasmaCore;
-import org.kde.plasma.components 2.0 as Plasma;
+import org.kde.plasma.components 3.0 as Plasma;
 import QtQuick.Layouts 1.3;
 
 PlasmaCore.Dialog {

src/scripts/desktopchangeosd/contents/ui/osd.qml

@@ -10,7 +10,6 @@ import QtQuick 2.0;
 import QtQuick.Window 2.0;
 import org.kde.plasma.core 2.0 as PlasmaCore;
 import org.kde.plasma.extras 2.0 as PlasmaExtras
-import org.kde.plasma.components 2.0 as Plasma;
 import org.kde.kquickcontrolsaddons 2.0 as KQuickControlsAddons;
 import org.kde.kwin 2.0;