[app] Rename and move var that used to set API URL

* PUBLIC_URL should now be provided as env var

app/client/.env.local

-REACT_APP_baseAPIURL=http://localhost:3000

app/client/src/utils/APICalls.js

 import axios from 'axios'
 
 const axiosInstance = axios.create({
-    baseURL: process.env.REACT_APP_baseAPIURL,
+    baseURL: process.env.PUBLIC_URL,
     withCredentials: true,
 });
 
@@ -16,7 +16,7 @@ axiosInstance.interceptors.response.use(
 );
 
 export const signout = () => {
-    return axiosInstance.post(process.env.REACT_APP_baseAPIURL + '/logout').then(user => {
+    return axiosInstance.post(process.env.PUBLIC_URL + '/logout').then(user => {
         // delete axiosInstance.defaults.headers.common["Authorization"];
         return user.data
     })
@@ -93,4 +93,4 @@ export const deleteTodo = (_id) => {
     }).then(todo => {
         return todo
     })
-}
+}
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