Major config overhaul: use custom modules, setup for multi-host config, and less boilerplate

modules/user/dmenu-scripts/default.nix

@@ -0,0 +1,14 @@
+{ config, lib, ...}:
+
+{
+  options = {
+    userSettings.dmenuScripts = {
+      enable = lib.mkEnableOption "Enable collection of dmenu scripts";
+      dmenuCmd = lib.mkOption {
+        default = "rofi -show dmenu";
+        description = "dmenu command";
+        type = lib.types.str;
+      };
+    };
+  };
+}