meta: reorganize nix-os and hosts to single directory nixos

nix-os/unstable-packages.nix

@@ -1,26 +0,0 @@
-{
-  config,
-  lib,
-  pkgs,
-  self,
-  ...
-}:
-
-let
-  cfg = config.unstable;
-  unstableOverlay = self.overlays.unstableWithMeta;
-in
-{
-  options.unstable = {
-    enable = lib.mkEnableOption ''
-      use of unstable packages in configuration. You can use `unstablePkgs` in configuration modules
-    '' // { default = true; };
-  };
-  config = {
-    _module.args.unstablePkgs = if config.unstable.enable then pkgs.unstable else pkgs;
-    nixpkgs.overlays = lib.mkIf cfg.enable [ unstableOverlay ];
-    system.extraSystemBuilderCmds = lib.mkIf config.unstable.enable ''
-      echo ${pkgs.unstableVersion} > $out/nixos-unstable-version
-    '';
-  };
-}