Security of tester accessors

The first commit of this merge request was introduced for zope4py3 branch but it revealed issues on py2 as well, i.e. we don't have roles in auto-generated tester methods.

```
======================================================================
FAIL: test_method_protection (testSecurity.TestSecurity)
This test will list all implicitly Public methods in any objects in ZODB.
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Traceback (most recent call last):
  File "/(SR)/parts/erp5/Products/ERP5/tests/testSecurity.py", line 113, in test_method_protection
    self.fail(message)
AssertionError: 
The following 7 methods have a docstring but have no security assertions.
	/(SR)/parts/erp5/product/ERP5Form/PreferenceTool.py:65 isPreferredVcsPushMode
	/srv/slapgrid/slappart19/t/eiy/soft/8a7759fd7b65b20d9f87713605745d05/parts/erp5/product/ERP5Type/Accessor/AcquiredProperty.py:217 hasTelephoneValidationState
	/(SR)/parts/erp5/product/ERP5Type/Accessor/Base.py:219 hasViewFormIdList
	/(SR)/parts/erp5/product/ERP5Type/Accessor/Constant.py:94 isWebDocumentType
	/(SR)/parts/erp5/product/ERP5Type/Accessor/Content.py:224 hasImage
	/(SR)/parts/erp5/product/ERP5Type/Accessor/ContentProperty.py:283 hasImageWidthList
	/(SR)/parts/erp5/product/ERP5Type/Accessor/Translation.py:233 hasFrTranslatedTitle

----------------------------------------------------------------------
```

See merge request nexedi/erp5!1911