Allow relative paths for jobs that use <commands on_exit_code="...">

Desired Behavior

• When adding an order to a job chain, it should be possible to specify a relative path to the job chain based on the location of the current job chain that executes the job that makes use of <commands on_exit_code="...">

Maintainer Notes

• This feature will not be provided for jobs that use the commands on_exit_code="..." element.
• This feature is provided for job nodes in job chains, see JS-1193.
• Due to technical constraints adding the relative path capability to standalone jobs would create more effort than we estimate to be efficient. The feature JS-1193 is the recommended way to achieve the same result for a job node.
• As standalone jobs will be retired in future releases we therefore suggest to move your standalone jobs to job chains if you require this functionality.