Appimage request

[usersteamdebian]

Add support for Appimage please, Flatpak it's one of the most bloated things that i ever tried on linux.

[anr2me]

Between AppImage, Flatpak, and Snap package, AppImage seems to be the better option.

I was working on creating AppImage on Alpine linux (chroot) before with ANR2MERefork#13, but it adds musl dependency, which isn't good (was discussed at #19295)

So now i'm working on it on Debian-based docker image instead of Alpine, but unfortunately, currently there is an segfault issue on the latest qemu that got fixed recently but seems to be regressed again a few days ago.

PS: The reason i use qemu is because i want to be able to build ppsspp on various CPU architectures.