[enhancement] think of possible config file for user to define tasks, dicom headers

[vsoch]

in the future, we would want the user to have more power to control tasks, and processing, and (given that the action to get the files lives outside the application) we should read this from some kind of config file, otherwise go to defaults. A better idea might be to have the user register the C-MOVE in the application, and specify these things when setting that up.