NPanelOverlay: implement wrapper for NPanel that opens in overlay layer

Widgets/NPanelOverlay.qml

@@ -0,0 +1,15 @@
+import QtQuick
+import Quickshell
+import Quickshell.Wayland
+import qs.Commons
+import qs.Services
+
+NPanel {
+  sourceComponent: Component {
+    // PanelWindow has its own screen property inherited of QsWindow
+    NPanelWindow {
+      loggerPrefix: "NPanelOverlay"
+      WlrLayershell.layer: WlrLayer.Overlay
+    }
+  }
+}