[wallpapers] Exposes a copy of the wallpaper so sddm can use it

[keth-real]

Pull Request

closes #1177 #1499
This is the easiest way to make the current wallpaper into a display-manager wallpaper. Or any system to access a file.

Make a copy of the file into /var/tmp/hyde/wall.set

Set current wallpaper as Sddm display picture

change Background=* into
Background="/var/tmp/hyde/wall.set" This is the path of the copied wallpaper.

Anyone can access this image so don't put anything confidential as the wallpaper. LOL

[abenezerw]

Actually you can give access to sddm by giving it reading privileges to the original location of the wall.set in cache.

[keth-real]

Actually you can give access to sddm by giving it reading privileges to the original location of the wall.set in cache.

You’re absolutely right—granting sddm read permissions to the original wallpaper location is a viable solution.

However, I wanted to clarify that this PR aims to expose the wallpaper system-wide, allowing not just sddm but also other applications to utilize it.

[keth-real]

Is there any way we don't hard code the user?

If we do this using $USER during the sddm session it is "root"

Background="/home/$USER/.cache/hyde/wall.set"

so we need to hard code it right?