Modify Remote Copy UI to allow for ~remote:: file specifications (not Dali)

Currently, it is a requirement that you provide a Dali IP to the Remote Copy dialog.
In the cloud this does not make sense (and in general WsDfs will be the required route).

There should either be an option to select the remote targets available (i.e. those that appear in planes.remote instead of requiring a dali IP, or, in the simplest implementation, the full logical file name along with the ~remote:: syntax can be specified.