Previously we used a combination of "provider.name" and "get_name()"
which was confusing. Using a non-property function also gave me the
impression that the name was more dynamic than it actually is.
If we set an environment variable, we can stub out calls to SES and send
them to our own stub app. If the environment variable is not set, things
work as normal.
To be used alongside
https://github.com/alphagov/notifications-email-provider-stub
