infra: Make Avalonia the default UI (#6375)

* misc: Move Ryujinx project to Ryujinx.Gtk3

This breaks release CI for now but that's fine.

Signed-off-by: Mary Guillemard <mary@mary.zone>

* misc: Move Ryujinx.Ava project to Ryujinx

This breaks CI for now, but it's fine.

Signed-off-by: Mary Guillemard <mary@mary.zone>

* infra: Make Avalonia the default UI

Should fix CI after the previous changes.

GTK3 isn't build by the release job anymore, only by PR CI.

This also ensure that the test-ava update package is still generated to
allow update from the old testing channel.

Signed-off-by: Mary Guillemard <mary@mary.zone>

* Fix missing copy in create_app_bundle.sh

Signed-off-by: Mary Guillemard <mary@mary.zone>

* Fix syntax error

Signed-off-by: Mary Guillemard <mary@mary.zone>

---------

Signed-off-by: Mary Guillemard <mary@mary.zone>

src/Ryujinx/UI/Controls/SliderScroll.axaml.cs

@@ -0,0 +1,31 @@
+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)
+        {
+            var newValue = Value + e.Delta.Y * TickFrequency;
+
+            if (newValue < Minimum)
+            {
+                Value = Minimum;
+            }
+            else if (newValue > Maximum)
+            {
+                Value = Maximum;
+            }
+            else
+            {
+                Value = newValue;
+            }
+
+            e.Handled = true;
+        }
+    }
+}