BatteryWidget: add low battery threshold

NSpinBox: add bootstrap icons

Modules/SettingsPanel/Bar/WidgetSettings/BatterySettings.qml

@@ -16,10 +16,13 @@ ColumnLayout {
   // Local state
   property bool valueAlwaysShowPercentage: widgetData.alwaysShowPercentage
                                            !== undefined ? widgetData.alwaysShowPercentage : widgetMetadata.alwaysShowPercentage
+  property int valueWarningThreshold: widgetData.warningThreshold
+                                      !== undefined ? widgetData.warningThreshold : widgetMetadata.warningThreshold
 
   function saveSettings() {
     var settings = Object.assign({}, widgetData || {})
     settings.alwaysShowPercentage = valueAlwaysShowPercentage
+    settings.warningThreshold = valueWarningThreshold
     return settings
   }
 
@@ -28,4 +31,14 @@ ColumnLayout {
     checked: root.valueAlwaysShowPercentage
     onToggled: checked => root.valueAlwaysShowPercentage = checked
   }
+
+  NSpinBox {
+    label: "Low battery warning threshold"
+    description: "Show a warning when battery falls below this percentage."
+    value: valueWarningThreshold
+    suffix: "%"
+    minimum: 5
+    maximum: 50
+    onValueChanged: valueWarningThreshold = value
+  }
 }