#311 Added domains element definition in memo.xsd

I think it's wrong. We should define domains in memo like this:

```xml
<memo>
  <domains>
    <domain>example.com</domain>
    <domain>example-2.com</domain>
  </domains>
  <ports>
    <port>80</port>
    <port>8080</port>
  </ports>
</memo>
```

This is how it will work in reality. We will forward all required port for all required domains to a Docker container. We simply can't have more precise configuration here, since Docker starts with a few open ports, for example, for this XML: 32124 and 32125. We should point both domains to them.