Improve Shipment file integration to support polling sftp protocol and File.

Transfer properties table supports the configuration of ftp as well as sftp protocols. It also supports the specification of local folder. Improve the implementation in so that both protocols can be supported.

Acceptance Criteria:

• poll interval is picked from environment

• appropriate ftp session beans are initialized to poll the sftp server if the protocol specified in transfer properties is "SFTP"

• appropriate file integration beans are initialized to poll the shared folder if the transfer_properties is for file/folder.