[ADD] unifrut: add stock quantity report based on fractions

This adds the new report of stock quantity per location
based on fractions in the Stock menu.

The report is based on the server action created by Humberto (hbto):
"[HBTO] (no-migrable) Reporte de Existencias por Ubicacion basado
en fracciones".

https://unifrut.odoo.com/web?debug=1#id=861&menu_id=4&cids=1&action=8&model=ir.actions.server&view_type=form

Related to #83450