feature(displaymanager): exchange gdm for sddm and configure astronaut theme

hosts/neon/configuration.nix

@@ -53,10 +53,24 @@
   # window manager configs
   programs.niri.enable = true;
   programs.xwayland.enable = true;
-  services.displayManager.gdm = {
+  services.displayManager.sddm = {
     enable = true;
-    wayland = true;
+    wayland = {
+      enable = true;
+    };
+    autoNumlock = true;
+    enableHidpi = true;
+    theme = "sddm-astronaut-theme";
+    settings = {
+      Theme = {
+        Current = "sddm-astronaut-theme";
+      };
+    };
+    extraPackages = with pkgs; [
+      sddm-astronaut
+    ];
   };
+
   services.tuned.enable = true;
   services.upower.enable = true;
 
@@ -110,6 +124,7 @@
     iotop
     iperf3
     jq
+    kdePackages.qtmultimedia
     kitty
     ldns
     lm_sensors
@@ -120,6 +135,7 @@
     nmap
     p7zip
     pciutils
+    sddm-astronaut
     socat
     strace
     sysstat