[REF] mass_mailing : Renaming Received stat into Delivered
[REF] mass_mailing : Renaming Received stat into Delivered

In order to be align between kanban view and form detailed view of mailing,
the name of the delivered mails have been aligned into a signle work : delivered.

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo