[FEATURE] Widgets that can ignore "exclusive" option

Description of the requested feature

Hi, let's get straight to a problem. [WAYLAND] I want to use eww as a wallpaper manager AND as a dock.

The problem is: my dock is exclusive, and I can't move wallpaper widget under it.

Look, there's a grey space at the top of the screen:

There's no option to move wallpaper widget under the dock, so dock moves my wallpaper a bit down.

Proposed configuration syntax

:ignore-exclusive true

Or:

:ignore-exclusive "[ignored window names]"

Additional context

I think you can make it like they did in some wallpaper managers, like swww or swaybg.