Add an option to not save token

Closes #252

DiscordChatExporter.Core.Services/SettingsService.cs

@@ -5,9 +5,11 @@ namespace DiscordChatExporter.Core.Services
 {
     public class SettingsService : SettingsManager
     {
+        public string DateFormat { get; set; } = "dd-MMM-yy hh:mm tt";
+
         public bool IsAutoUpdateEnabled { get; set; } = true;
 
-        public string DateFormat { get; set; } = "dd-MMM-yy hh:mm tt";
+        public bool IsTokenPersisted { get; set; } = true;
 
         public AuthToken? LastToken { get; set; }
 
@@ -21,5 +23,7 @@ namespace DiscordChatExporter.Core.Services
             Configuration.SubDirectoryPath = "";
             Configuration.FileName = "Settings.dat";
         }
+
+        public bool ShouldSerializeLastToken() => IsTokenPersisted;
     }
 }

DiscordChatExporter.Gui/ViewModels/Dialogs/SettingsViewModel.cs

@@ -7,16 +7,22 @@ namespace DiscordChatExporter.Gui.ViewModels.Dialogs
     {
         private readonly SettingsService _settingsService;
 
+        public string DateFormat
+        {
+            get => _settingsService.DateFormat;
+            set => _settingsService.DateFormat = value;
+        }
+
         public bool IsAutoUpdateEnabled
         {
             get => _settingsService.IsAutoUpdateEnabled;
             set => _settingsService.IsAutoUpdateEnabled = value;
         }
 
-        public string DateFormat
+        public bool IsTokenPersisted
         {
-            get => _settingsService.DateFormat;
-            set => _settingsService.DateFormat = value;
+            get => _settingsService.IsTokenPersisted;
+            set => _settingsService.IsTokenPersisted = value;
         }
 
         public SettingsViewModel(SettingsService settingsService)

DiscordChatExporter.Gui/Views/Dialogs/SettingsView.xaml

@@ -41,6 +41,21 @@
                 IsChecked="{Binding IsAutoUpdateEnabled}" />
         </DockPanel>
 
+        <!--  Persist token  -->
+        <DockPanel
+            LastChildFill="False"
+            Background="Transparent"
+            ToolTip="Persist last used token between sessions">
+            <TextBlock
+                Margin="16,8"
+                DockPanel.Dock="Left"
+                Text="Save token" />
+            <ToggleButton
+                Margin="16,8"
+                DockPanel.Dock="Right"
+                IsChecked="{Binding IsTokenPersisted}" />
+        </DockPanel>
+
         <!--  Save button  -->
         <Button
             Margin="8"