Enable users to drag and drop a USS file into a PDS

[adam-wolfe]

Is your feature request related to a problem? Please describe.

To insert a file from USS into a PDS, users currently have to download the USS file, then upload the file to a member, which is a bit cumbersome.

Describe the solution you'd like

As we further develop drag and drop capabilities in V3, we could also allow users to drag and drop a file from USS into a PDS. Additionally, it could be useful to allow users to drag and drop a data set or member into the USS file tree.

Describe alternatives you've considered

Manually download the USS file, then upload the file to a PDS.

Additional context