[Client] Add shuffle players option and turn order dialog

Adds the 'Shuffle players at start' checkbox to game creation and a
host-only 'Set turn order...' action that opens a dialog to reorder or
randomize the seats before the game starts. Seating changes are shown in
the game's message log.

cockatrice/src/interface/widgets/dialogs/dlg_turn_order.h

@@ -0,0 +1,46 @@
+/**
+ * @file dlg_turn_order.h
+ * @ingroup GameDialogs
+ */
+//! \todo Document this file.
+
+#ifndef DLG_TURN_ORDER_H
+#define DLG_TURN_ORDER_H
+
+#include <QDialog>
+#include <QStringList>
+
+class QListWidget;
+class QPushButton;
+
+class DlgTurnOrder : public QDialog
+{
+    Q_OBJECT
+private:
+    QListWidget *listWidget;
+    QPushButton *moveUpButton;
+    QPushButton *moveDownButton;
+    QPushButton *randomizeButton;
+    bool randomizeRequested;
+
+    void moveSelected(int delta);
+    void updateButtons();
+
+private slots:
+    void actMoveUp();
+    void actMoveDown();
+    void actRandomize();
+    void actOk();
+    void selectionChanged();
+
+public:
+    explicit DlgTurnOrder(const QStringList &_playerNames, QWidget *parent = nullptr);
+
+    [[nodiscard]] bool randomize() const
+    {
+        return randomizeRequested;
+    }
+    [[nodiscard]] QStringList order() const;
+};
+
+#endif