Publish to nixpkgs and/or add a flake so that the editor may be installed via Nix/on NixOS

[Flamarine]

NixOS doesn't have a proper FHS environment and thus many standalone applications won't work without special patches.

I currently use nix-alien as a temporary solution, which is a bit wacky. Therefore I think it's better to have a proper publication on nixpkgs. Adding a flake to the repository to make it build on NixOS should also be okay.