Add interface binding to FTP adapters

Current implementation of FTP adapters (EnsLib.FTP.InboundAdapter, EnsLib.FTP.OutboundAdapter) lack a property to force binding with a specific TCP interface, similar to EnsLib.TCP.Common.LocalInterface.

Being able to select a specific interface simplify the configuration of security components (firewalls, proxies, ...) between the IRIS instance and the remote FTP server.