Contributor GH profile email: also add to alias_email row in the contributor_alias table

Right now when an email is retrieved from the GH profile information it is only added to the cntrb_email column in the contributors table. This change would have those emails also added to the contributor_alias table so all of the email are in one place.

This is the last functional step to get the alias_email column to have all of the emails associated with a contributor. This would allow for the eventual change where the contributor_alias table can be transformed to the contributor_email (not specific on the name) table with the alias_email column to be cntrb_email and be the one place to look for cntrb_id -> email mapping.