[applets/devicenotifier] Re-add "show popup when new device is plugged in" option

This was removed in
https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/185,
however the original reasons for making the change no longer apply
because we now have a clean place to put the option--in the new popup
menu in the header. So let's re-add it, because hidden options are bad.
:)

BUG: 430017
FIXED-IN: 5.20

applets/devicenotifier/package/contents/config/main.xml

@@ -18,7 +18,6 @@
       <label>If true it lists all kind of devices. Only one between removableDevices, nonRemovableDevices and allDevices should be set.</label>
       <default>false</default>
     </entry>
-    <!-- This option has no visible UI and is only accessible by adding "popupOnNewDevice=false" to the plasma-org.kde.plasma.desktop-appletsrc file-->
     <entry name="popupOnNewDevice" type="Bool">
       <label>If true it tries to open the plasmoid when a new device is inserted, as a kind of notification.</label>
       <default>true</default>

applets/devicenotifier/package/contents/ui/devicenotifier.qml

@@ -228,6 +228,7 @@ Item {
     property var showRemovableDevicesAction
     property var showNonRemovableDevicesAction
     property var showAllDevicesAction
+    property var openAutomaticallyAction
 
     Component.onCompleted: {
         if (sdSource.connectedSources.count === 0) {
@@ -254,6 +255,13 @@ Item {
 
         plasmoid.setActionSeparator("sep");
 
+        plasmoid.setAction("openAutomatically", i18n("Show popup when new device is plugged in"));
+        devicenotifier.openAutomaticallyAction = plasmoid.action("openAutomatically");
+        devicenotifier.openAutomaticallyAction.checkable = true;
+        devicenotifier.openAutomaticallyAction.checked = Qt.binding(() => {return plasmoid.configuration.popupOnNewDevice;});
+
+        plasmoid.setActionSeparator("sep2");
+
         if (devicenotifier.openAutomounterKcmAuthorized) {
             plasmoid.setAction("openAutomounterKcm", i18nc("Open auto mounter kcm", "Configure Removable Devices..."), "configure")
         }
@@ -281,6 +289,10 @@ Item {
         plasmoid.configuration.allDevices = true;
     }
 
+    function action_openAutomatically() {
+        plasmoid.configuration.popupOnNewDevice = !plasmoid.configuration.popupOnNewDevice;
+    }
+
     Plasmoid.onExpandedChanged: {
         popupEventSlot(plasmoid.expanded);
     }