Update README.md

Update README.md

Update readme and screenshots

added app icons and splash screen, changed the login UI

added fade transition for all screens/routes for app

animation added to auth screen

added animation manual controller for login,singup -Auth widget

added signin and signup with firebase authentication api

Alertnative way to calling api calls using FutureBuilder and Consumer

Pushing order data to firebase and retrieving order data from firebase database

implemented update and delete functionality to manage products

Used Snackbar, AlertDialog and added funcitonality for adding products

Merge branch 'main' of https://github.com/rajeshmadasu/eShoppingCart

Displaying a list of cart items, deletion, 2. dsiplaying product detail data , 3.Adding an Orders screen ,4. Navigation side drawer

updated readme