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/core/settings.h

@@ -12,6 +12,11 @@
 
 namespace Settings {
 
+enum class InitClock {
+    SystemTime = 0,
+    FixedTime = 1,
+};
+
 enum class LayoutOption {
     Default,
     SingleScreen,
@@ -106,8 +111,10 @@ struct Values {
     // Data Storage
     bool use_virtual_sd;
 
-    // System Region
+    // System
     int region_value;
+    InitClock init_clock;
+    u64 init_time;
 
     // Renderer
     bool use_hw_renderer;