[test] make unittest_webconfig independant of CWD if apphome is unset in ApptestConfiguration constructor, this later looks for a 'data' directory in CWD, making this test runnable only from web/test (and pytest do chdir before executing tests, so we did not noticed this problem).

Add some entities
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As manager, you can access to entity creation forms by using the `site management`_ page.

.. _`site management`: manage

As regular user, the index page or the action box may propose some links to create entities according to the context.