added core config for important runtime modules such as mono

configuration.nix

@@ -20,6 +20,7 @@ in
     ./.luks-swap.nix
     ./fonts.nix
     ./extra
+    ./core/
   ];
 
   hardware.bluetooth.enable = true;

core/default.nix

@@ -0,0 +1,5 @@
+{
+    imports = [
+        ./dotnet.nix
+    ];
+}

core/dotnet.nix

@@ -0,0 +1,6 @@
+{ pkgs, config, ... }: {
+    environment.systemPackages = with pkgs; [
+        dotnet-sdk
+        mono
+    ];
+}