Move menu constants to menu section

src/shared.js

@@ -0,0 +1,20 @@
+export const Directions = {
+	LEFT: -1,
+	RIGHT: 1,
+};
+
+let debug = location.hostname === "127.0.0.1";
+
+/**
+ * @returns {boolean} Whether debug mode is enabled
+ */
+export function isDebug() {
+	return debug;
+}
+
+/**
+ * @param {boolean} debugMode
+ */
+export function setDebug(debugMode) {
+	debug = debugMode;
+}