citra-qt: Move config dialog code to its own directory

src/citra_qt/configuration/configure_system.h

@@ -0,0 +1,37 @@
+// Copyright 2016 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <QWidget>
+
+namespace Ui {
+class ConfigureSystem;
+}
+
+class ConfigureSystem : public QWidget {
+    Q_OBJECT
+
+public:
+    explicit ConfigureSystem(QWidget* parent = nullptr);
+    ~ConfigureSystem();
+
+    void applyConfiguration();
+    void setConfiguration();
+
+public slots:
+    void updateBirthdayComboBox(int birthmonth_index);
+
+private:
+    void ReadSystemSettings();
+
+    std::unique_ptr<Ui::ConfigureSystem> ui;
+    bool enabled;
+
+    std::u16string username;
+    int birthmonth, birthday;
+    int language_index;
+    int sound_index;
+};