[autoform] Avoid two calls to field.process_form for the same field in some cases when some entity is being created and data include non-inlined relations, the values for this relation are now stored for later usage, avoiding two calls to field's process_form method, which may be unexpected for custom fields. This has been discovered in saem_ref#f5444b1f9770. Reorganize imports in the test along the way.

missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules)
embedded-javascript-library usr/share/cubicweb/cubes/shared/data/jquery.js