Add command line interface and change solution structure (#26)

DiscordChatExporter.Gui/App.ammy.cs

@@ -0,0 +1,19 @@
+using System.Windows;
+
+namespace DiscordChatExporter.Gui
+{
+    public partial class App
+    {
+        private Container Container => (Container) Resources["Container"];
+
+        private void App_Startup(object sender, StartupEventArgs e)
+        {
+            Container.Init();
+        }
+
+        private void App_Exit(object sender, ExitEventArgs e)
+        {
+            Container.Cleanup();
+        }
+    }
+}