Initial work on a setup wizard

Setup wizard abstraction & architecture from TKMM

src/Ryujinx/UI/SetupWizard/RyujinxSetupWizard.cs

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+using Avalonia.Controls.Presenters;
+using Ryujinx.Ava.Common.Locale;
+using Ryujinx.Ava.Systems.Configuration;
+using Ryujinx.Ava.Systems.SetupWizard;
+using Ryujinx.Ava.UI.ViewModels;
+using Ryujinx.Common.Logging;
+using Ryujinx.UI.SetupWizard;
+using Ryujinx.UI.SetupWizard.Pages;
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using Logger = Ryujinx.Common.Logging.Logger;
+
+namespace Ryujinx.Ava.UI.SetupWizard
+{
+    public class RyujinxSetupWizard(ContentPresenter presenter, MainWindowViewModel mwvm, Action onClose) : BaseSetupWizard(presenter)
+    {
+        private bool _configWasModified = false;
+
+        public bool HasFirmware => mwvm.ContentManager.GetCurrentFirmwareVersion() != null;
+
+        public override async ValueTask Start()
+        {
+            RyujinxSetupWizardWindow.IsUsingSetupWizard = true;
+            Start:
+            await FirstPage();
+
+            Keys:
+            if (!mwvm.VirtualFileSystem.HasKeySet)
+            { 
+                Retry:
+                SetupKeysPageViewModel kpvm = new();
+                bool result = await NextPage()
+                    .WithTitle(LocaleKeys.SetupWizardKeysPageTitle)
+                    .WithContent<SetupKeysPage>(kpvm)
+                    .Show();
+
+                if (!result)
+                    goto Start;
+
+                if (!Directory.Exists(kpvm.KeysFolderPath))
+                    goto Retry;
+
+                await mwvm.HandleKeysInstallation(kpvm.KeysFolderPath);
+            }
+
+            Firmware:
+            // ReSharper disable once ConditionIsAlwaysTrueOrFalse
+            // i know its always false thats the fucking point, its not done
+            if (!HasFirmware && false)
+            {
+                if (!mwvm.VirtualFileSystem.HasKeySet)
+                    goto Keys;
+                
+                Retry:
+                SetupKeysPageViewModel kpvm = new();
+                bool result = await NextPage()
+                    .WithTitle(LocaleKeys.SetupWizardKeysPageTitle)
+                    .WithContent<SetupKeysPage>(kpvm)
+                    .Show();
+                
+                if (!result)
+                    goto Keys;
+
+                if (!Directory.Exists(kpvm.KeysFolderPath))
+                    goto Retry;
+
+                await mwvm.HandleKeysInstallation(kpvm.KeysFolderPath);
+            }
+
+            Return:
+            onClose();
+
+            if (_configWasModified)
+                ConfigurationState.Instance.ToFileFormat().SaveConfig(Program.GlobalConfigurationPath);
+        }
+    }
+}