Feature: Configurable game ending year

Functionally reverts 683b65ee1

src/settings_gui.cpp

@@ -1698,6 +1698,7 @@ static SettingsContainer &GetSettingsTree()
 			genworld->Add(new SettingEntry("economy.town_layout"));
 			genworld->Add(new SettingEntry("difficulty.industry_density"));
 			genworld->Add(new SettingEntry("gui.pause_on_newgame"));
+			genworld->Add(new SettingEntry("game_creation.ending_year"));
 		}
 
 		SettingsPage *environment = main->Add(new SettingsPage(STR_CONFIG_SETTING_ENVIRONMENT));