misc: Move StatusBarSeparator into Controls namespace, rename to MiniVerticalSeparator

add bulk property change event method
give each markup extension its own property name

src/Ryujinx/UI/Controls/SliderScroll.cs

@@ -0,0 +1,18 @@
+using Avalonia.Controls;
+using Avalonia.Input;
+using System;
+
+namespace Ryujinx.Ava.UI.Controls
+{
+    public class SliderScroll : Slider
+    {
+        protected override Type StyleKeyOverride => typeof(Slider);
+
+        protected override void OnPointerWheelChanged(PointerWheelEventArgs e)
+        {
+            Value = Math.Clamp(Value + e.Delta.Y * TickFrequency, Minimum, Maximum);
+
+            e.Handled = true;
+        }
+    }
+}