[IMP] sale_stock: decrease ordered qty log impacted pickings

When the user decrease the quantity on the SO it will log the
activity on a the upsteam documents however the user can't easily
find the impacted documents linked to it. In order to achieve that
the _get_upstream_documents_and_responsibles method pass a stack
that remember all the documents browsed in order to return the final
document. This stack is then passed in the _render_method in log activity
in order to use it when rendering the note for the activity.