DEPiP: Desktop Extended Picture-in-Picture

### Description of the new feature / enhancement

Have a Picture-in-Picture window view of the content shown on a 2nd monitor/extended display to make it easier to control/verify from the primary monitor view. I'll be working on a PoC for this feature as part of Microsoft Hackathon.

### Scenario when this would be used?

When extending your desktop to a 2nd monitor/TV/projector that you can't directly see but still want to be able to control or view the content on that extended display.

### Supporting information

While at a Speed Jigsaw Puzzle event recently, the host needed to show a timer on a TV that was facing away from them to the competitor while being able to separately enter times for the competitors on their main laptop display. Because of this, they had to walk around the table to control the TV with a wireless mouse, instead of being able to do it from their laptop view.

The issue names no files, tests, or entry points. Start by locating the PowerToys component responsible for displaying or controlling content on an extended monitor, then define how a picture-in-picture view would interact with that display. Done means the secondary-display content can be viewed and controlled from the primary monitor without moving to the extended display.

Written by the indexing model from the issue text.