restructure

- users/rin/default.nix -> users/rin.nix
- users/rin/home.nix +-> users/rin.nix
- users/rin/*.nix -> modules/user/*.nix
- users/rin/scripts/ -> scripts/
- hosts/winter/default.nix -> hosts/winter.nix
- hosts/winter/*.nix -> modules/system/*.nix

- modules are dynamically imported as sets for system and user

hosts/winter/default.nix

@@ -1,48 +0,0 @@
-{ config, overlays, pkgs, ... }: {
-  networking.hostName = "winter";
-  system.stateVersion = "20.09";
-
-  environment.etc = {
-    "machine-id".source = "/var/persist/machine-id";
-    "ssh/ssh_host_rsa_key".source = "/var/persist/ssh_host_rsa_key";
-    "ssh/ssh_host_rsa_key.pub".source = "/var/persist/ssh_host_rsa_key.pub";
-    "ssh/ssh_host_ed25519_key".source = "/var/persist/ssh_host_ed25519_key";
-    "ssh/ssh_host_ed25519_key.pub".source = "/var/persist/ssh_host_ed25519_key.pub";
-  };
-  environment.pathsToLink = [ "/share/zsh" ];
-  users.mutableUsers = false;
-
-  imports = [
-    ./audio.nix
-    ./gui.nix
-    ./hardware-configuration.nix
-    ./kernel.nix
-    ./networking.nix
-    ./packages.nix
-    ./security.nix
-    ./snapper.nix
-
-    ../../users/rin
-  ];
-  nix = rec {
-    package = pkgs.nixUnstable;
-    binaryCaches = [
-      "https://cache.nixos.org?priority=10"
-      "https://lava.cachix.org"
-    ];
-    binaryCachePublicKeys = [
-      "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
-      "lava.cachix.org-1:8lTWI/3IKWHByzzYHZySunMPYs2eAJw2duL+uLZkSy0="
-    ];
-    trustedBinaryCaches = binaryCaches;
-
-    extraOptions = ''
-      experimental-features = nix-command flakes
-    '';
-  };
-  nixpkgs.config.allowUnfree = true;
-
-  i18n.defaultLocale = "en_GB.UTF-8";
-  console.useXkbConfig = true;
-}
-