Support DMARC

[david-a-wheeler]

Add support for "Domain-based Message Authentication, Reporting & Conformance" (DMARC). This is an email authentication, policy, and reporting protocol - basically it provides stronger evidence to receivers that the sender is who it claims to be, and also gets reports on failures. It builds on the SPF and DKIM protocols. We send email; we want ensure that users are more likely to receive it, and counter those who would want to forge our email messages. More info: https://dmarc.org/

A lot of this is probably just configuring DNS servers appropriately using the SendGrid info. See:

https://sendgrid.com/docs/Glossary/dkim.html https://sendgrid.com/docs/Classroom/Deliver/Sender_Authentication/internet_standards_spf_and_dkim_and_deliverability.html https://sendgrid.com/docs/Classroom/Deliver/Sender_Authentication/spf_records_explained.html