Register some settings for the system, including some developer-only settings

module/settings/dev_settings.mjs

@@ -0,0 +1,9 @@
+export default function() {
+	game.settings.register(`dotdungeon`, `devMode`, {
+		scope: `client`,
+		type: Boolean,
+		config: false,
+		default: false,
+		requiresReload: false,
+	});
+};