Add support for Argon2 hashing algorithm in Password Dialog

OpenLDAP 2.5 supports Argon2 as hash algorithm for the userPassword attribute. The Password editor cannot display the attribute correctly like for SSHA, and cannot verify it.

Sample of possible value:

$argon2i$v=19$m=4096,t=3,p=1$Dl0N1HndOAtsJSbbMv5WWQ$hJqQ2JdQFLlGyyqocwTZC6sLuK6VF5T40qlN5uDsjAM