added backend api url to config, uses in api_util files

ecom-web/src/config.js

 class Config {
-    static baseApiUrl = "http://localhost:8080/api"; //env file
-    static orderHistoryApiUrlMethod = (userId) => `${this.baseApiUrl}/orders/byUser/${userId}`;
+    static baseApiUrl = "http://localhost:8080"; //env file
+    static orderHistoryApiUrlMethod = (userId) => `${this.baseApiUrl}/api/orders/byUser/${userId}`;
 
 
 }

ecom-web/src/util/product_api_util.js

 import axios from 'axios';
+import Config from '../config';
 
 export const fetchProducts = () => {
-    return axios.get("http://localhost:8080/api/products")
+    return axios.get(`${Config.baseApiUrl}/api/products`)
 }
 
 export const fetchPromotions = () => {
-    return axios.get("http://localhost:8080/api/promos")
+    return axios.get(`${Config.baseApiUrl}/api/promos`)
 }
 
 export const fetchProductsAndPromotions = () => {
-    return axios.get("http://localhost:8080/api/products-and-promos")
+    return axios.get(`${Config.baseApiUrl}/api/products-and-promos`)
 }
\ No newline at end of file

ecom-web/src/util/session-api-util.js

 import axios from 'axios';
+import Config from '../config';
 
 export const postUser = (user) => {
-    return axios.post("http://localhost:8080/api/users", user)
+    return axios.post(`${Config.baseApiUrl}/api/users`, user)
 }
 
 // export const postUser = (user) => {