Users: password changes via the web UI now use Argon2

Co-authored-by: Graham Christensen <graham@grahamc.com>

Created by  Graham Christensen  on April 15, 2021
QA7SEIVP756UUYM5SEXOLEONOG5M2XS3QSL4A4BP2LXHA3EG2AUQC
Change contents