Amazon SES Support

[ainsleyclark]

Amazon SES provider for Go Mail, see below for implentation.

• https://docs.aws.amazon.com/ses/latest/APIReference/API_SendEmail.html

[kaptinlin]

any update?

[ainsleyclark]

Requires quite a bit of refactoring using the SMTP client. If I have time I will add it, but welcome pull requests.