Keyboard Shortcut For Power Display Settings

### Description of the new feature / enhancement

Assigning keyboard shortcuts to (for example) increase and decrease brightness of the display monitor in Power Display

### Scenario when this would be used?

My keyboard has several redefinable Function Keys and I can use them to adjust brightness or other settings available in Power Display.
If more than one monitor connected it would be better to assign key shortcuts to each of them separately.

### Supporting information

_No response_

No files, tests, or entry points are named in the issue. Start by locating Power Display's existing setting controls and any keyboard shortcut handling, then clarify which settings and per-monitor behavior are in scope; done means users can assign shortcuts for display brightness or other supported Power Display settings.

Written by the indexing model from the issue text.