JOE should suppress default values in configuration files

Current Situation

• JOE writes XML elements and attributes as stated in the editor GUI.
• This includes that elements and attributes are created that present the default values for JobScheduler.
• Example: <job_chain orders_recoverable="yes" visible="yes"

Desired Behavior

• For better readability and compatibility with future changes of default values JOE should not write values that represent defaults for JobScheduler.

Notes

• <job_chain orders_recoverable="yes" visible="yes"
• <... let_run="no"
• empty <params>"
• empty <remote_schedulers>"
• but empty <run_time>" are still in the xml because of JS-474