[Feature Request] Package as Flatpak

[amethystgosling163]

This will make it so users don't have to add a repo to install your program on any distro that has a Software Center with Flatpak support, as users can just install it from there. This also aids the discoverability of the program as users can find it while browsing the Software Center for such a program.

[AlynxZhou]

I personally don't use flatpak so I will probably have no time on maintaining a flatpak version, if anyone is interested in maintaining a flatpak version I will be grateful.