Bar widgets: modular loading refactoring via BarWidgetRegistry+NWidgetLoader

- Hot reload is working again.
- Should also be more memory efficient on multi monitors.

Modules/Bar/Widgets/Volume.qml

@@ -9,12 +9,15 @@ import qs.Widgets
 Item {
   id: root
 
-  width: pill.width
-  height: pill.height
+  property ShellScreen screen
+  property real scaling: ScalingService.scale(screen)
 
   // Used to avoid opening the pill on Quickshell startup
   property bool firstVolumeReceived: false
 
+  implicitWidth: pill.width
+  implicitHeight: pill.height
+
   function getIcon() {
     if (AudioService.muted) {
       return "volume_off"
@@ -64,6 +67,7 @@ Item {
       }
     }
     onClicked: {
+      var settingsPanel = PanelService.getPanel("settingsPanel")
       settingsPanel.requestedTab = SettingsPanel.Tab.AudioService
       settingsPanel.open(screen)
     }