[openssl/openssl] c77fb9: Add Argon2 KDF demo.

[Milan Broz]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: c77fb9af5595fa416637f775e51722699ea3c78b
      https://github.com/openssl/openssl/commit/c77fb9af5595fa416637f775e51722699ea3c78b
  Author: Milan Broz <gmazyland at gmail.com>
  Date:   2023-03-21 (Tue, 21 Mar 2023)

  Changed paths:
    M demos/kdf/Makefile
    A demos/kdf/argon2.c

  Log Message:
  -----------
  Add Argon2 KDF demo.

Signed-off-by: Milan Broz <gmazyland at gmail.com>

Reviewed-by: Matt Caswell <matt at openssl.org>
Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20531)