Update README.md

release: launch Version 3

feature: complete Currency Converter

code: convert from currency to another screen

code: Update Currency rate

code: add currency searching

feature: add Currencies Exchange app => add currencies list screen, code currency class

code,fix: code transfer screen and class for transactions , change transactions logic

code: add hi admin name in dashboard

doc_code: doc coment to explain code

fix,code,doc: rename Config.h to Global.h and refactor, code check admin permissions before going to Screens and code Error Screen, doc some notes

code,test,fix,doc,launch: code tirm functions, test trim functions, fix bugs apper when add space after username while login and some typos, doc how to run v2 of app, launch v2.0.0

test: test app manually and fix bugs

fix: fix all client and admin Operations to fit new logic , adding some improvements

fix,code: fix presintation layer logic and change architicture, code to fit new logic