XD-1303 JobInstance REST endpoint

- Add ResourceAssembler that builds JobInstanceInfoResource out
of JobInstanceInfo domain object
- Added REST endpoint /batch/instances/{instanceId} that returns
the job instance for a given instanceId
- Updated the existing REST endpoint /batch/jobs/{jobName}/instances
to return jobExecutions along with the given jobInstance
- Refactored Batch controllers
 - Created AbstractBatchJobsController that can be extended by XD batch
job admin controllers
 - Removed NoSuchJobException and used NoSuchBatchJobException by moving
the logic to update message when there is no job name