refactor: make the whole thing more generic

modules/nixos/fonts/nerdfonts.nix

@@ -0,0 +1,26 @@
+{ pkgs, lib, config, ... }:
+with lib;
+
+let cfg = config.fonts.nerdfonts;
+
+in {
+  options.fonts.nerdfonts = {
+    enable = mkEnableOption "Enable nerdfonts";
+    additionalFonts = mkOption {
+      type = types.listOf types.str;
+      default = [ ];
+      description = "Additional fonts to include in the nerdfonts package";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    fonts = {
+      packages = with pkgs;
+        [
+          (nerdfonts.override {
+            fonts = [ "NerdFontsSymbolsOnly" ] ++ cfg.additionalFonts;
+          })
+        ];
+    };
+  };
+}