Emailvalidation

[lakshyajit165]

Fixes #183

The functionality to check if an email is valid is complete. @PrathamDogra, @adavijit @rajatmw1999, please review this. Note: A free tier plan for the APIlayer service has been used in this (as discussed with mentors). Please let others know about it that, this service allows 250 requests per month and 33/250 requests have already been made for the month of April 2020. I will also post about this is the slack group so that no one exhausts the limit by making unnecessary requests

[rajatmw1999]

Great job @lakshyajit165

[lakshyajit165]

Thanks @rajatmw1999 😊