[migration/3.18] Add add_permission relation definitions earlier
Otherwise sync_schema_props_perms('defaultval') does not work because the
later relation is not in schema.
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.