XD-360 Add support for creating a spring batch job that references a named trigger

The purpose of this PR is to allow a user to create a Job using a trigger or cron expression 
Examples are
http://localhost:8080/jobs?name=wombat&definition=Job%20--cron='*/10%20*%20*%20*%20*%20*'
-or-
http://localhost:8080/jobs?name=triggerwombat&definition=Job%20--trigger=mytrigger