Store the job progress in a separated live file

The idea is to extract the progress data in a dedicated file outside of the status.xml. It should also ideally be stored live to reduce the pressure on the memory like for the log since it can something be very big in jobs doing many thing (like a migration executing a lot of requests).

It produce huge content that are not always required when looking at the status and also make the status.xml file more fragile and unreadable by a human.