refactor: add a popup panel to show submodule updating status

src/Views/Repository.axaml.cs

@@ -306,16 +306,10 @@ namespace SourceGit.Views
             e.Handled = true;
         }
 
-        private async void UpdateSubmodules(object sender, RoutedEventArgs e)
+        private void UpdateSubmodules(object sender, RoutedEventArgs e)
         {
             if (DataContext is ViewModels.Repository repo)
-            {
-                repo.SetWatcherEnabled(false);
-                iconSubmoduleUpdate.Classes.Add("rotating");
-                await Task.Run(() => new Commands.Submodule(repo.FullPath).Update());
-                iconSubmoduleUpdate.Classes.Remove("rotating");
-                repo.SetWatcherEnabled(true);
-            }
+                repo.UpdateSubmodules();
 
             e.Handled = true;
         }

src/Views/UpdateSubmodules.axaml

@@ -0,0 +1,17 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:vm="using:SourceGit.ViewModels"
+             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
+             x:Class="SourceGit.Views.UpdateSubmodules"
+             x:DataType="vm:UpdateSubmodules">
+  <StackPanel Orientation="Vertical" Margin="8,0">
+    <TextBlock FontSize="18"
+               Classes="bold"
+               Text="{DynamicResource Text.UpdateSubmodules}"/>
+    <TextBlock Text="{DynamicResource Text.UpdateSubmodules.Tip}"
+               Margin="0,16,0,0"
+               HorizontalAlignment="Center"/>
+  </StackPanel>
+</UserControl>

src/Views/UpdateSubmodules.axaml.cs

@@ -0,0 +1,12 @@
+using Avalonia.Controls;
+
+namespace SourceGit.Views
+{
+    public partial class UpdateSubmodules : UserControl
+    {
+        public UpdateSubmodules()
+        {
+            InitializeComponent();
+        }
+    }
+}