[ADD] mail: send email based on templates
[ADD] mail: send email based on templates

When performing automatic tracking it is now possible to automatically send
emails based on a template. This template can either be a qweb template
using its xml_id or a MailTemplate using its record.

This is simply implementing directly in the mixing a feature already present
in recruitment and soon to be added in task, issues or helpdek.

hip-odoo/odoo,dfang/odoo,ygol/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo,ygol/odoo,dfang/odoo,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,hip-odoo/odoo,hip-odoo/odoo,dfang/odoo,ygol/odoo,dfang/odoo,dfang/odoo,dfang/odoo