Function: Copies files or folders from the specified server using scp.
Author: Douglas Stebila
Requires: scp must be able to automatically authenticate with the client, for example, using ssh public key authentication.
Notes: Warning: This action may overwrite files on the local computer. Note that if any input files are provided, then the files or folders downloaded are added to the list of input files in the output. This allows you to use multiple Download with scp actions to download a set of files and process them all together at the end.