od-unix: show controller-backed hardfiles like Windows

od-unix: show controller-backed hardfiles like Windows

Mirror Windows in the mounted-drive list for hardfiles attached to IDE,
SCSI, or custom controllers. Show the controller target instead of the
Amiga device name, and mark the boot priority as not applicable.

Keep RDB hardfiles on non-UAE controllers in the same state when they
are edited or saved. The Qt dialog clears the Device field, hides the
boot-priority controls, and serializes stale device names back to the
empty Windows-style value.