changes were also applied to DC workflow, which should not be changed

rename files my_default_expr.xml to my_default_expression.xml
rename default_expr to default_expression in xml files and scripts

ERP5Workflow: add variable to avoid multiple call to function and remove successive 'if/continue' for readability

ERP5Workflow: revert more changes (some Property Sheets have been moved to erp5_workflow bt5, they are back to product/ERP5/bootstrap)

- erp5_test_workflow
  *  add testWorklowMixin test case for inheritance purpose,
  *  move testWorklist ERP5 test to portal_component

author: Wenjie Zheng

Dependency should be defined directly on bt5 if needed.

'keep_existing' argument of Base._edit has never been used
and we should consider removing it.

When defining a guard on an object, calling
a method such as Base_viewDict on that object
could be denied due to guard acquisition.

- the check is moved to a less performance-critical place
- getPortalObject was forgotten in commit d8e9ed19

- 'apply' causes a break in cProfile results
- 'apply' is deprecated (removed in Python 3)

* reference
* translated_title
* the usual owner_title, creation_date and modification_date
* remove useless listbox_editable_fields that are defined in the field library

This business template does not seem to follow the guideline yet