Ability to send a receipt / order confirmation to customer

To be able to meet our obligations to OFCOM when using Powerlynx in the UK, we must be able to send the customer a confirmation of the service they have signed up for (e.g. the plan they select) after sign-up and a link to the T&Cs they agreed to.

Ideally this could be an email where we can fill out a template and insert variables for the values (e.g. $plan_selected, $plan_cost, $start_date )