重构MainWindow的主界面

使用主窗口自带标题栏，摒弃侧栏和几个按钮独立的SideBarVLay，将之合并到原标题栏中

inc/spkmainwindow.h

@@ -157,16 +157,10 @@ namespace SpkUi
       SpkMainWidget(QWidget *parent = nullptr);
 
       QHBoxLayout *HorizontalDivide;
-      QVBoxLayout *VLayMain;
-      SpkTitleBar *TitleBar;
 
       QStackedWidget *Pager;
 
       // Category widget is for switching pages
-      QWidget *SideBarRestrictor;
-      QVBoxLayout *VLaySidebar;
-      QHBoxLayout *HLaySideTop;
-      QLabel *StoreIcon;
       SpkIconButton *BtnSettings, *BtnFeedback, *BtnLogs, *BtnDayNight, *BtnBack;
       SpkSidebarTree *CategoryWidget;
       QMap<int, QTreeWidgetItem> *CategoryItemMap;

inc/spktitlebar.h

@@ -46,7 +46,7 @@ class SpkTitleBar : public QWidget
     using OperationButton = SpkTitleBarDefaultButton::OperationButton;
     void SetOperationButton(OperationButton);
 
-    void SetIcon(QPixmap &p) { mIcon->setPixmap(p); }
+    void SetIcon(QPixmap p) { mIcon->setPixmap(p); }
     void SetTitle(QString t) { mTitle->setText(t); }
     QString GetTitle() { return mTitle->text(); }
     void SetUseIcon(bool t) { mIcon->setVisible(t); }