Move Nix files into a nix directory

Move everything from `config` to the root level.

modules/nixos/desktop/default.nix

@@ -1,9 +0,0 @@
-{
-  imports = [
-    ../.
-    ./fonts.nix
-    ./gitea.nix
-    ./jellyfin.nix
-    ./immich.nix
-  ];
-}

modules/nixos/desktop/fonts.nix

@@ -1,36 +0,0 @@
-{ pkgs, ... }:
-
-let
-  theme = import ../../../lib/theme { inherit pkgs; };
-in
-{
-  environment.systemPackages = with pkgs; [
-    terminus_font
-    terminus_font_ttf
-  ];
-
-  fonts = {
-    fontconfig = {
-      enable = true;
-      defaultFonts = {
-        monospace = [ theme.fonts.monospace.name ];
-      };
-    };
-
-    packages =
-      with pkgs;
-      [
-        (nerdfonts.override {
-          fonts = [
-            "AnonymousPro"
-            "FiraCode"
-            "GeistMono"
-            "IntelOneMono"
-            "Iosevka"
-            "JetBrainsMono"
-          ];
-        })
-      ]
-      ++ [ theme.fonts.monospace.package ];
-  };
-}

modules/nixos/desktop/gitea.nix

@@ -1,17 +0,0 @@
-{ pkgs, ... }:
-
-{
-  services.gitea = {
-    enable = true;
-
-    settings = {
-      server = {
-        HTTP_PORT = 2222;
-      };
-
-      service = {
-        DISABLE_REGISTRATION = true;
-      };
-    };
-  };
-}

modules/nixos/desktop/immich.nix

@@ -1,7 +0,0 @@
-{ pkgs, ... }:
-
-{
-  services.immich.enable = true;
-
-  environment.systemPackages = [ pkgs.immich-cli ];
-}

modules/nixos/desktop/jellyfin.nix

@@ -1,6 +0,0 @@
-{
-  services.jellyfin = {
-    enable = true;
-    openFirewall = true;
-  };
-}