Make Alfresco FTP PASV work with Docker NAT

[AFaust]

When the Alfresco Repository runs inside a Docker container, it will use the local address of the container to respond to FTP PASV commands. This address will not be resolvable by FTP clients and cause FTP connections to fail. Some FTP clients, like WinSCP, may be able to force the use of the public address used for establishing the initial connection instead of using the server-provided local address. In the long run, the Docker setup requires that Alfresco FTP provide the proper public address so it can be used with all FTP clients. This might require a patch / contribution to the JLAN project to support a configurable public address.

[AFaust]

MNT-16433 already requests this type of enhancement for the Alfresco product.