emails with verbose name supported across the board

Signed-off-by: LeGast00n
Don't we already have `validate_email_with_name` function on [Line 9](https://github.com/ui/django-post_office/blob/master/post_office/validators.py#L9) though? Can't we use that instead?

I think it's cleaner to have one single function doing all the email with name validation across the entire library.