PTFM-10479: Add "workflow" to dx-jobutil-add-output as an allowed output class

- Also add analysis references support
- Tests
PTFM-10559: Remove support for record-based workflows

- Remove dxpy.DXRecordWorkflow and rename dxpy.DXAnalysisWorkflow to
  dxpy.DXWorkflow
- Remove some unnecessary imports and general cleanup
Add dxpy support for workflow instance type requests at runtime
Add dxpy support for referring to stages by name

- Also, some doc cleanup