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/Helpers/TimeZoneConverter.cs

@@ -0,0 +1,28 @@
+using Avalonia.Data.Converters;
+using System;
+using System.Globalization;
+using TimeZone = Ryujinx.Ava.UI.Models.TimeZone;
+
+namespace Ryujinx.Ava.UI.Helpers
+{
+    internal class TimeZoneConverter : IValueConverter
+    {
+        public static TimeZoneConverter Instance = new();
+
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            if (value == null)
+            {
+                return null;
+            }
+
+            var timeZone = (TimeZone)value;
+            return string.Format("{0}  {1}   {2}", timeZone.UtcDifference, timeZone.Location, timeZone.Abbreviation);
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}