* Rename WorkflowConfigurator PropertySheet to ConfiguratorWorkflow.
* Add ConfiguratorWorkflowTransition PropertySheet for transition_form_id.
  => Should it be moved to standard 'action' instead?
* Avoid defining Configurator-specific API in Workflow API, such as
  initializeDocument(). TODO: What about:
  - state.getAvailableTransitionList()
  - state.executeTransition()
  - state.getWorkflowHistory()
  - state.undoTransition()
  => erp5_configurator_standard:testStandardConfigurationWorkflow