BATCH-2007: Added a JobOperator impl that complies with JSR-352

* Added JsrJobOperator
* Added a ParametersConverter (and JSR-352 implementation) that converts parameters as specified by the JSR to JobParameters and back
* Added a method to the JobRepository to allow the direct creation of a JobInstance (since the JSR requires a new instance for each call to JobOperator#start
* Added a base context to be bootstrapped when the JobOperator is first referenced.  It provides things like a JobRepository, etc.