Moved secrets in God email notifications config to secrets.yml. It is no longer necessary to have per-environment versions of the notifications.god file.

Also some monkeypatching to fix STARTTLS support when God sends emails via SMTP now happens in all environments, instead of just in production and staging.

The notifications.god file has an if/else to make the config different depending on the environment (production/staging send their emails through SMTP, other environments send them to root@localhost via sendmail). I see no easy way to remove this if/else, so it stays.