ERP5Site.py: check the action provider list after the workfkow tool migration, add portal_workflow if it was not in the list; clean up.

erp5_workflow_test_data: check woerkflow history with expected contents dict to make sure the history contents are correct.

InteractionWorkflow.py: in showAsXML deploy expression getter; turn property_value into empty string when it is an empty tuple.

ERP5/InteractionWorkflow.py: get interaction guard expression text instead of callable object in showAsXML.

patches/DCWorkflow.py: get transition guard expression text instead of callable object in showAsXML.

deal with empty transition guard expression in conversion.

WorkflowTool.py: resolve the error when state has no premission_roles, matrix index should not be generated.

erp5_workflow: remove unecessesary tales in transition expression. tale can be pass as string type in this case.