CORE-4090 Fix for InputOutputMap in AnalysisImporter.

Updated AnalysisImporter::importObject method to prevent a org.hibernate.PropertyValueException (not-null property references a transient value) when updating an existing multi-step analysis (workflow/pipeline).
Added a session reference to AnalysisImporter, so that InputOutputMaps could be deleted and the session flushed before their associated TransformationSteps are deleted.
Added an AnalysisImporter::saveAnalysis method to save the workflow and its new TransformationSteps before saving its new InputOutputMaps.
Added cascade="none" to TransformationStep relations in the InputOutputMap in workflow.hbm.xml in order to prevent the transient value exception when deleting InputOutputMaps.
This cascade setting caused the transient value exception when creating new multi-step workflows, so the same saveAnalysis method must be used for new workflows as well.
CORE-4090 import/updateWorkflow now return IDs.

Updated WorkflowImporter::importWorkflowElements to return a JSON object with a JSON array of IDs for each type it imports.
Updated importWorkflow, updateWorkflow, and forceUpdateWorkflow in WorkflowImportService to return this JSON object.