System: Store game hash as well as serial

src/core/game_database.h

@@ -88,6 +88,7 @@ void EnsureLoaded();
 void Unload();
 
 const Entry* GetEntryForDisc(CDImage* image);
+const Entry* GetEntryForId(const std::string_view& code);
 const Entry* GetEntryForSerial(const std::string_view& serial);
 std::string GetSerialForDisc(CDImage* image);
 std::string GetSerialForPath(const char* path);