feat: update action manager

- add and delete some actions in action manager.
- rename "fit to view" to "fit to screen".
- update main window right click menu and toolbar.
- use special state update slot in action manager instead of function located in main window.

app/mainwindow.h

@@ -66,39 +66,38 @@ protected:
     QSize sizeHint() const override;
 
 private slots:
-    void on_actionOpen_triggered();
-
-    void on_actionActualSize_triggered();
-    void on_actionToggleMaximize_triggered();
-    void on_actionZoomIn_triggered();
-    void on_actionZoomOut_triggered();
-    void on_actionToggleCheckerboard_triggered();
-    void on_actionRotateClockwise_triggered();
-    void on_actionRotateCounterClockwise_triggered();
+    void on_actionCopyPixmap_triggered();
+    void on_actionCopyFilePath_triggered();
 
     void on_actionPrevPicture_triggered();
     void on_actionNextPicture_triggered();
 
+    void on_actionActualSize_triggered();
+    void on_actionFitToScreen_triggered();
+    void on_actionFitByWidth_triggered();
+    void on_actionFitByHeight_triggered();
+    void on_actionZoomIn_triggered();
+    void on_actionZoomOut_triggered();
+
+    void on_actionFlipHorizontal_triggered();
+    void on_actionFlipVertical_triggered();
+    void on_actionRotateClockwise_triggered();
+    void on_actionRotateCounterClockwise_triggered();
+
+    void on_actionToggleAvoidResetTransform_triggered();
+    void on_actionToggleCheckerboard_triggered();
     void on_actionTogglePauseAnimation_triggered();
     void on_actionAnimationNextFrame_triggered();
 
-    void on_actionHorizontalFlip_triggered();
-    void on_actionFitInView_triggered();
-    void on_actionFitByWidth_triggered();
-    void on_actionCopyPixmap_triggered();
-    void on_actionCopyFilePath_triggered();
-    void on_actionPaste_triggered();
     void on_actionTrash_triggered();
-    void on_actionToggleAvoidResetTransform_triggered();
+    void on_actionLocateInFileManager_triggered();
+    void on_actionProperties_triggered();
+
     void on_actionSettings_triggered();
     void on_actionHelp_triggered();
-    void on_actionProperties_triggered();
-    void on_actionLocateInFileManager_triggered();
-    void on_actionQuitApp_triggered();
 
 private:
     bool updateFileWatcher(const QString & basePath = QString());
-    void updateGalleryButtonsVisibility();
 
 private:
     ActionManager *m_am;