Add custom refresh rate mode to VSync option (#238)

Rebased @jcm93's refreshinterval branch:
https://github.com/jcm93/Ryujinx/tree/refreshinterval

The option is placed under System/Hacks. Disabled, it's the default
Ryujinx behavior. Enabled, the behavior is shown in the attached
screenshots. If a framerate is too high or low, you can adjust the value
where you normally toggle VSync on and off. It will also cycle through
the default on/off toggles.

Also, in order to reduce clutter, I made an adjustment to remove the
target FPS and only show the percentage.

---------

Co-authored-by: jcm <6864788+jcm93@users.noreply.github.com>

src/Ryujinx/Assets/Styles/Styles.xaml

@@ -1,7 +1,8 @@
 <Styles
     xmlns="https://github.com/avaloniaui"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    xmlns:ui="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia">
+    xmlns:ui="clr-namespace:FluentAvalonia.UI.Controls;assembly=FluentAvalonia"
+    xmlns:windowing="clr-namespace:FluentAvalonia.UI.Windowing;assembly=FluentAvalonia">
     <Design.PreviewWith>
         <Border Height="2000"
                 Padding="20">
@@ -231,7 +232,7 @@
         <Setter Property="BorderBrush"
                 Value="{DynamicResource HighlightBrush}" />
     </Style>
-    <Style Selector="Button">
+    <Style Selector="Button:not(windowing|MinMaxCloseControl Button)">
         <Setter Property="MinWidth"
                 Value="80" />
     </Style>

src/Ryujinx/UI/Windows/AboutWindow.axaml

@@ -6,8 +6,10 @@
     xmlns:ext="clr-namespace:Ryujinx.Ava.Common.Markup"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:viewModel="clr-namespace:Ryujinx.Ava.UI.ViewModels"
-    Width="550"
-    Height="260"
+    MinWidth="550"
+    MinHeight="260"
+    MaxWidth="600"
+    MaxHeight="500"
     Margin="0,-12,0,0"
     d:DesignHeight="260"
     d:DesignWidth="550"