add option to override user attributes from SSO payload

add an external_username attribute for username from SSO payload

repair the field name in SingleSignOnRecord migration

move setting of external_username for sso to controller

add settings toggle to override username/email from SSO payload

fix changing of external username after override toggle

complete tests and logic for sso override

add some extra context to username override option

add external_email and external_name to single sign on record

add setting for name override from SSO payload

complete override with stored external_email and external_name

add missing checks to tests

remove an unneeded describe block