* Add new configuration for multi-domain relay hosts (#922)
* Creates new environment variables (replacing existing AWS_SES variables)
* Optionally allows more advanced setups using config files
* Update relay hosts during change detection (#922)
* Add helper scripts for adding relay hosts and per-domain auth
* Allow the possibility to deliver some mail directly
* adding a domain with no destination will exclude it from the
relayhost_map and so Postfix will attempt to deliver the mail directly
* tests for setup.sh script
* tests for relay host configuration
* these tests cover the code in `start-mailserver.sh` dealing with both
the env vars and the configuration files
* fix for issue #747 (NOT TESTED YET)
Need to test this. Dont merge it yet.
* Small Cleanup and bug fixes Not done Yet!
Not done yet. Dont merge. See comment in issue #747
* Add --ignore-missing. Now is fixed.
