Implement core_privacy for auth plugins (not oauth2 and manual)

These changes are covered by the unit tests for the manager. Also, you can testing by running the attached testwithmanager.php script (see ------- MDL-61571 ------- for the original script location) in the Moodle root folder. Make sure you've purged the cache (php admin/cli/purge_caches.php), before running testwithmanager.php. You should receive a script output like in Moodle 3.5 and 3.4: Testing the compliant plugins: ... == auth_cas (auth_cas\privacy\provider) == Claims not to store any data with reason: 'The CAS server (SSO) authentication plugin does not store any personal data.' == auth_db (auth_db\privacy\provider) == Claims not to store any data with reason: 'The External database authentication plugin does not store any personal data.' == auth_email (auth_email\privacy\provider) == Claims not to store any data with reason: 'The Email-based self-registration authentication plugin does not store any personal data.' == auth_ldap (auth_ldap\privacy\provider) == Claims not to store any data with reason: 'The LDAP server authentication plugin does not store any personal data.' == auth_lti (auth_lti\privacy\provider) == Claims not to store any data with reason: 'The LTI authentication plugin does not store any personal data.' == auth_mnet (auth_mnet\privacy\provider) == Claims not to store any data with reason: 'The MNet authentication plugin does not store any personal data.' == auth_nologin (auth_nologin\privacy\provider) == Claims not to store any data with reason: 'The No login authentication plugin does not store any personal data.' == auth_none (auth_none\privacy\provider) == Claims not to store any data with reason: 'The No authentication plugin does not store any personal data.' == auth_shibboleth (auth_shibboleth\privacy\provider) == Claims not to store any data with reason: 'The Shibboleth authentication plugin does not store any personal data.' == auth_webservice (auth_webservice\privacy\provider) == Claims not to store any data with reason: 'The Web services authentication plugin does not store any personal data.' ... You should receive a script output like in Moodle 3.3: (auth_imap, auth_pop3, auth_pam, auth_nntp added) Testing the compliant plugins: == auth_cas (auth_cas\privacy\provider) == Claims not to store any data with reason: 'The CAS server (SSO) authentication plugin does not store any personal data.' == auth_db (auth_db\privacy\provider) == Claims not to store any data with reason: 'The External database authentication plugin does not store any personal data.' == auth_email (auth_email\privacy\provider) == Claims not to store any data with reason: 'The Email-based self-registration authentication plugin does not store any personal data.' == auth_fc (auth_fc\privacy\provider) == Claims not to store any data with reason: 'The FirstClass server authentication plugin does not store any personal data.' == auth_imap (auth_imap\privacy\provider) == Claims not to store any data with reason: 'The IMAP server authentication plugin does not store any personal data.' == auth_ldap (auth_ldap\privacy\provider) == Claims not to store any data with reason: 'The LDAP server authentication plugin does not store any personal data.' == auth_lti (auth_lti\privacy\provider) == Claims not to store any data with reason: 'The LTI authentication plugin does not store any personal data.' == auth_mnet (auth_mnet\privacy\provider) == Claims not to store any data with reason: 'The MNet authentication plugin does not store any personal data.' == auth_nntp (auth_nntp\privacy\provider) == Claims not to store any data with reason: 'The NNTP server authentication plugin does not store any personal data.' == auth_nologin (auth_nologin\privacy\provider) == Claims not to store any data with reason: 'The No login authentication plugin does not store any personal data.' == auth_none (auth_none\privacy\provider) == Claims not to store any data with reason: 'The No authentication plugin does not store any personal data.' == auth_pam (auth_pam\privacy\provider) == Claims not to store any data with reason: 'The PAM (Pluggable Authentication Modules) authentication plugin does not store any personal data.' == auth_pop3 (auth_pop3\privacy\provider) == Claims not to store any data with reason: 'The POP3 server authentication plugin does not store any personal data.' == auth_shibboleth (auth_shibboleth\privacy\provider) == Claims not to store any data with reason: 'The Shibboleth authentication plugin does not store any personal data.' == auth_webservice (auth_webservice\privacy\provider) == Claims not to store any data with reason: 'The Web services authentication plugin does not store any personal data.'