Allow to read the supplier value when creating quotation lines
One may be interested on customizing the lines values depending on the supplier used but this is not currently possible because the field is not available on the request:
https://hg.tryton.org/modules/purchase_request_quotation/file/1789591561e2/purchase.py#l524
So I think we should factorize the method to pass also the newly created quotation so we can read the supplier and other values.