User.archive does not remove entries in the identifiers table

[briri]

The User.archive method was introduced several years ago and has not kept up with the recent changes. It should be updated to clear out any entries in the identifiers table (Shibboleth user ids and ORCIDs) that are related to the user.

A script would then need to be run to purge these records for any user accounts that have already been archived.

[dsisu]

Also see issue #2680