nix: replace sddm with greetd

enables autologin
display manager is ttygreet

modules/linux/login.nix

@@ -1,20 +1,16 @@
 { config, lib, pkgs, ... }:
 
 {
-  services.displayManager.sddm = {
+  services.greetd = {
     enable = true;
-    wayland.enable = true;
-    theme = "where_is_my_sddm_theme_qt5";
+    settings = {
+      initial_session = {
+        command = "${pkgs.hyprland}/bin/Hyprland";
+        user = "nico";
+      };
+      default_session = {
+        command = "${pkgs.greetd.tuigreet}/bin/tuigreet --asterisks --time --greeting 'nyaaa~~'";
+      };
     };
-
-  environment.systemPackages = with pkgs; [
-    (pkgs.where-is-my-sddm-theme.override {
-      variants = [ "qt5" ];
-      themeConfig.General = {
-        background = pkgs.nixos-artwork.wallpapers.nineish-dark-gray.gnomeFilePath;
-        backgroundMode = "fill";
-        cursorColor = "#ffffff";
   };
-   })
-  ];
 }