Linux flatpack/AppImage other rpm/.deb

[Dracks]

To continue the discussion opened in my P/R: https://github.com/gameflorist/dunedynasty/pull/6

Will be nice to have some flatpack, appimage or similar, since I've got a linux as a personal laptop, I will try to investigate and generate.

The only issue I see is how to work with the external data, since should not be anymore relative to the executable and should be in the user directory or some global/system directory. But first things first, create some packed app for linux.

Note: I cannot assign it to me :(