Add: company mode enforcement checks to functions with command or company access

Command functions are those that call ScriptObject::Command, and functions
with company access are any that call ScriptObject::GetCompany. This is a bit
over-protective, but having the check everywhere makes it easier to validate
that no check is missing automatically instead of by review.

src/script/api/script_station.hpp

@@ -287,6 +287,7 @@ public:
 	/**
 	 * Toggle the open/closed state of an airport.
 	 * @param station_id The airport to modify.
+	 * @game @pre ScriptCompanyMode::IsValid().
 	 * @pre IsValidStation(station_id).
 	 * @pre HasStationType(station_id, STATION_AIRPORT).
 	 * @return True if the state was toggled successfully.