create a validation process for contributor emails

[rbbeeston]

on the User profile, there is another ticket (#1709 ) to add a button to link a contributor email address that was previously used. This process would be a pop up that would ask for a valid email, and then send an email verification link to that address. when clicked it would add that name to the profile and merge it with the current github email in the commit authors DB

It's possible that the address is no longer valid, if possible if we can detect if it bounces that it could notify a dev to check the email against the earlier mailing list and see if it matches with the user. It could then me added manually.