Further optimisation of system user creation

roles/docker-pixelfed/templates/env.j2

@@ -48,10 +48,10 @@ RESTRICTED_INSTANCE=false
 MAIL_DRIVER=log
 MAIL_HOST={{system_email.host}}
 MAIL_PORT={{system_email.port}}
-MAIL_FROM_ADDRESS="{{system_email.from}}"
+MAIL_FROM_ADDRESS="{{ users['no-reply'].email }}"
 MAIL_FROM_NAME="Pixelfed"
-MAIL_USERNAME={{system_email.username}}
-MAIL_PASSWORD={{system_email.password}}
+MAIL_USERNAME={{ users['no-reply'].email }}
+MAIL_PASSWORD={{ users['no-reply'].mailu_token }}
 # Not sure if the following is correct
 # Checkout: https://github.com/pixelfed/pixelfed/blob/dev/.env.docker
 MAIL_ENCRYPTION={{ 'ssl' if system_email.start_tls else 'tls' }}