Add a new subtype_id for 'RFQ Sent' state. This removes the need to join on mail.tracking.value when computing 'all_sent_rfqs'. Since mail.tracking.value is usually a big table, removing this join leads to a substantial speedup when loading the purchase.order dashboard on big databases. closes odoo/odoo#96921 Signed-off-by: Arnold Moyaux (arm) <arm@odoo.com>