Add support for PrefersNonDefaultGPU desktop specification

[Yousuf 'Jay' Philips]

This is an enhancement report, so that support for .desktop specification can be added.

https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html#recognized-keys

PrefersNonDefaultGPU [Boolean] = If true, the application prefers to be run on a more powerful discrete GPU if available, which we describe as "a GPU other than the default one" in this spec to avoid the need to define what a discrete GPU is and in which cases it might be considered more powerful than the default GPU. This key is only a hint and support might not be present depending on the implementation.

It is being used by gnome
https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1226
https://www.phoronix.com/scan.php?page=news_item&px=GNOME-Desktop-File-dGPU-Option
https://www.gamingonlinux.com/articles/the-linux-desktop-entry-specification-gets-a-way-to-automatically-use-a-discrete-gpu-merged-into-gnome.16598