Generate a Desktop icon on Linux

[Avasam]

Is your feature request related to a problem? Please describe.

So as far as I understand it, Linux is dumb with icons and doesn't let you ship an icon as part of the file.
So what if instead we just ran some variant of gio set ./AutoSplit.elf metadata::custom-icon file://./icon.ico during boot? The icon will show up after first launch :)
Here's a possible sensible location to extract the icon into:
https://martin.hoppenheit.info/blog/2016/where-to-put-application-icons-on-linux/
https://specifications.freedesktop.org/icon-theme-spec/icon-theme-spec-0.13.html#install_icons
/usr/share/icons/hicolor/256x256/apps/AutoSplit.png

Describe the solution you'd like

If the executable has an icon after the first use, that is sufficient for me.

Describe alternatives you've considered

https://github.com/orgs/pyinstaller/discussions/7599 (there's some valid relevant info in that discussion)

Additional context

Extracted from #224