sonata_type buttons changes
Merge branch 'sonata_type_buttons' into c_prod

Conflicts:
	Resources/doc/reference/form_field_definition.rst
	Resources/views/CRUD/edit_orm_many_to_many.html.twig
	Resources/views/CRUD/edit_orm_many_to_one.html.twig
	Resources/views/CRUD/edit_orm_one_to_many.html.twig
	Resources/views/CRUD/edit_orm_one_to_one.html.twig
	Resources/views/Form/form_admin_fields.html.twig