Method job_chain.add_or_replace_order() should return replaced order

Current Situation

• The sos.spooler.Job_chain.add_or_replace_order() method of JobScheduler Master does not provide a return value, thus there is no information whether an order has been added or replaced.

Desired Behavior

• The information whether an order has been added or replaced should be returned:
  • add: a return value null signals that the order has been added
  • replace: the original order that has been replaced is returned