Opt-out option for monthly pdf invoices

[vohmar]

Registrar accepting e-invoices has requested for opting out from receiving pdf invoices via email. We do not have this option as we are trying to send e-invoices to every registrar and system does not have information who actually receives them. So automation is tricky. But we could add an option for registrars to opt-out manually from receiving the invoices via email.

Checkbox?

• Add this option to registrar portal profile view
• Add this option to admin interface under registrar billing details (so admin can check the status and if necessary change the setting)
• Add an unsubscribe option to invoice email?