Add plymouth

nixos_common.nix

@@ -35,8 +35,31 @@
         enable = true;
         efiSupport = true;
         device = "nodev";
+        timeoutStyle = "hidden";
       };
     };
+
+    initrd = {
+      systemd.enable = true;
+      verbose = false;
+    };
+
+    consoleLogLevel = 0;
+
+    kernelParams = [
+      "quiet"
+      "splash"
+      "boot.shell_on_fail"
+      "loglevel=3"
+      "rd.systemd.show_status=false"
+      "rd.udev.log_level=3"
+      "udev.log_priority=3"
+    ];
+
+    plymouth = {
+      enable = true;
+      theme = "bgrt";
+    };
   };
 
   services = {