Move mapreduce.task.timeout configuration out of workflow definition

[marekhorst]

We should consider moving mapreduce.task.timeout configuration out of workflow.xml file to externally defined config-default.xml file to allow easy reconfiguration without the need of modifying part of IIS code.

In the beginning it was considered as pretty static value but it turned not to be the case as it was modified several times already.

Originally posted by @marekhorst in https://github.com/openaire/iis/issues/933#issuecomment-459804506