OrderAdded and OrderRemoved Events should be sent

Current Situation

• If the order queue of a job is changed, e.g. with a <modify_order at="now+10".../> or a scheduled order gets no task when the JobScheduler is paused then no event is sent.
• If an order is removed then no event is sent.

Desired Behavior

• JOC Cockpit needs information if an order is added or removed to update the order and job chain view.
• JobScheduler should send an OrderAdded and an OrderRemoved event.
• Both events have the "key":"/path/to/jobChain,orderId"
• OrderAdded should have the "nodeId" field.