feature<Cleanup>: add toolbar button to run git gc and git lfs prune

src/Views/Popups/Cleanup.xaml.cs

@@ -0,0 +1,34 @@
+using System.Threading.Tasks;
+
+namespace SourceGit.Views.Popups {
+    /// <summary>
+    ///     清理仓库
+    /// </summary>
+    public partial class Cleanup : Controls.PopupWidget {
+        private string repo;
+
+        public Cleanup(string repo) {
+            this.repo = repo;
+            InitializeComponent();
+        }
+
+        public override string GetTitle() {
+            return App.Text("Dashboard.Clean");
+        }
+
+        public override Task<bool> Start() {
+            UpdateProgress(GetTitle());
+
+            return Task.Run(() => {
+                Models.Watcher.SetEnabled(repo, false);
+                new Commands.GC(repo, UpdateProgress).Exec();
+
+                var lfs = new Commands.LFS(repo);
+                if (lfs.IsEnabled()) lfs.Prune(UpdateProgress);
+
+                Models.Watcher.SetEnabled(repo, true);
+                return true;
+            });
+        }
+    }
+}