Add mail/py-email-validator: Robust email address syntax and deliverability validation library

This library validates that address are of the form x@y.com. This is the sort
of validation you would want for a login form on a website.

Key features:

• Good for validating email addresses used for logins/identity.
• Friendly error messages when validation fails (appropriate to show to end users).
• (optionally) Checks deliverability: Does the domain name resolve?
• Supports internationalized domain names and (optionally) internationalized local parts.
• Normalizes email addresses (super important for internationalized addresses!)

WWW: https://github.com/JoshData/python-email-validator

PR: 246039
Submitted by: Goran Mekić <meka@tilda.center>