How do we setup a process for automated emails to be sent based on a customer response. For example, when a mail gets sent from my end, and if the customer has replied back to it, a mail should be sent automatically thanking for the reply, and incase the customer hasn't replied back to the mail, Odoo should notice that no reply has been received for the mail sent and a follow-up mail should be sent automatically. How do we make this work in Odoo?