BATCHADM-179: Allow step and job execution context to be retrieved over the rest.
Updates for BATCHADM-179

* Update copyright dates
* Replace wildcard imports
* General formatting
* Utilize Errors object rather than logging
* Move ObjectMapper creation from class to bean
* Remove unused schema from manager-context
* Rename context.json end points to exection-context.json
* Add conditional check for stepExecutionContext in step/executionContext.ftl
* Remove redundant jobInfo/jobInfo.jobInstance conditional in jobs/executions.ftl