UserInterface: add universal opacity slider (except for bar)

LauncherTab: remove opacity slider
Settings: add migration
i18n: add opacity slider translation

Modules/Panels/Launcher/Launcher.qml

@@ -21,8 +21,6 @@ SmartPanel {
 
   exclusiveKeyboard: true
 
-  panelBackgroundColor: Qt.alpha(Color.mSurface, Settings.data.appLauncher.backgroundOpacity)
-
   // Positioning
   readonly property string panelPosition: {
     if (Settings.data.appLauncher.position === "follow_bar") {

Modules/Panels/Settings/Tabs/LauncherTab.qml

@@ -49,37 +49,6 @@ ColumnLayout {
     }
   }
 
-  ColumnLayout {
-    spacing: Style.marginXXS
-    Layout.fillWidth: true
-
-    NText {
-      text: I18n.tr("settings.launcher.settings.background-opacity.label")
-      pointSize: Style.fontSizeL
-      font.weight: Style.fontWeightBold
-      color: Color.mOnSurface
-    }
-
-    NText {
-      text: I18n.tr("settings.launcher.settings.background-opacity.description")
-      pointSize: Style.fontSizeXS
-      color: Color.mOnSurfaceVariant
-      wrapMode: Text.WordWrap
-      Layout.fillWidth: true
-    }
-
-    NValueSlider {
-      id: launcherBgOpacity
-      Layout.fillWidth: true
-      from: 0.0
-      to: 1.0
-      stepSize: 0.01
-      value: Settings.data.appLauncher.backgroundOpacity
-      onMoved: value => Settings.data.appLauncher.backgroundOpacity = value
-      text: Math.floor(Settings.data.appLauncher.backgroundOpacity * 100) + "%"
-    }
-  }
-
   NToggle {
     label: I18n.tr("settings.launcher.settings.clipboard-history.label")
     description: I18n.tr("settings.launcher.settings.clipboard-history.description")

Modules/Panels/Settings/Tabs/UserInterfaceTab.qml

@@ -119,6 +119,27 @@ ColumnLayout {
       }
     }
 
+    // Panel Background Opacity
+    ColumnLayout {
+      spacing: Style.marginXXS
+      Layout.fillWidth: true
+
+      NLabel {
+        label: I18n.tr("settings.user-interface.panel-background-opacity.label")
+        description: I18n.tr("settings.user-interface.panel-background-opacity.description")
+      }
+
+      NValueSlider {
+        Layout.fillWidth: true
+        from: 0
+        to: 1
+        stepSize: 0.01
+        value: Settings.data.ui.panelBackgroundOpacity
+        onMoved: value => Settings.data.ui.panelBackgroundOpacity = value
+        text: Math.floor(Settings.data.ui.panelBackgroundOpacity * 100) + "%"
+      }
+    }
+
     NDivider {
       Layout.fillWidth: true
       Layout.topMargin: Style.marginL