feat: centralize the base url config in frontend js part

frontend/config.js

@@ -0,0 +1,3 @@
+export const config = {
+    baseURL: "http://localhost:8080"
+};

frontend/src/dashboardApp.js

@@ -1,4 +1,6 @@
-const baseUrl = "http://localhost:8080/dashboard.php";
+import { config } from "../config";
+
+const baseUrl = `${config.baseURL}/dashboard.php`;
 
 export function dashboardApp() {
   return {

frontend/src/invoiceApp.js

@@ -1,5 +1,7 @@
-const baseUrl = "http://localhost:8080/invoice.php";
-const menuBaseUrl = "http://localhost:8080/menu.php";
+import { config } from "../config";
+
+const baseUrl = `${config.baseURL}/invoice.php`;
+const menuBaseUrl = `${config.baseURL}/menu.php`;
 
 export function invoiceApp() {
   return {

frontend/src/menuApp.js

@@ -1,4 +1,6 @@
-const baseUrl = "http://localhost:8080/menu.php";
+import { config } from "../config";
+
+const baseUrl = `${config.baseURL}/menu.php`;
 
 export function menuApp() {
   return {