added module for sddm astronaut theme

modules/astronaut/default.nix

@@ -0,0 +1,36 @@
+args@{ config, lib, pkgs, ... }:
+
+let
+    cfg = config.sddmAstronautTheme or {};
+    sddm-astronaut-theme = import ./derivation.nix (args // {
+        theme = cfg.subtheme;
+        themeOverrides = cfg.themeOverrides;
+    });
+in {
+    options.sddmAstronautTheme = {
+        enable = lib.mkEnableOption "sddm astronaut theme";
+        subtheme = lib.mkOption {
+            type = lib.types.str;
+            default = "astronaut";
+            description = "Which subtheme of the sddm astronaut theme to use.";
+        };
+        themeOverrides = lib.mkOption {
+            type = lib.types.attrsOf lib.types.str;
+            default = {};
+            description = "Overrides for options specified in the selected theme.conf.";
+        };
+    };
+
+    config = lib.mkIf cfg.enable {
+        # Apply the configuration value to the derivation
+        environment.systemPackages = [
+            sddm-astronaut-theme
+        ];
+
+        services.displayManager.sddm.extraPackages = with pkgs.kdePackages; [
+            qtsvg
+            qtmultimedia
+            qtvirtualkeyboard
+        ];
+    };
+}