Add system time configuration (#4043)

* Add setting to switch between a fixed start time and the system time

Add clock settings to SDL

Make clock configureable in qt

Add a SharedPage handler class

Init shared_page_handler for tests

src/citra_qt/configuration/configure_system.h

@@ -31,10 +31,12 @@ public:
 
 public slots:
     void updateBirthdayComboBox(int birthmonth_index);
+    void updateInitTime(int init_clock);
     void refreshConsoleID();
 
 private:
     void ReadSystemSettings();
+    void ConfigureTime();
 
     std::unique_ptr<Ui::ConfigureSystem> ui;
     bool enabled;