Lift setting / vertical / barSize onto BarWidget

Six widgets (clock, daytime, keyboardLayout, lockKeys, activeWindow,
media) shipped identical copies of `function setting(name, fallback)`.
Eight widgets reimplemented `readonly property bool vertical`, and
three reimplemented `readonly property int barSize`. Move all three
onto the BarWidget base so widgets read the same wiring everyone else
gets for free.

While in here, drop the dead `setting()` declaration on media.qml — it
was defined but never called.

shell/plugins/bar/widgets/workspaces.qml

@@ -8,9 +8,6 @@ BarWidget {
   id: root
   moduleName: "workspaces"
 
-  readonly property bool vertical: bar ? bar.vertical : false
-  readonly property int barSize: bar ? bar.barSize : Style.bar.sizeHorizontal
-
   function workspaceById(id) {
     var values = Hyprland.workspaces.values
     for (var i = 0; i < values.length; i++) {