Implement DES ECB encrypt via EVP_CIPHER api

Implement DES ECB encrypt via EVP_CIPHER api

Even though DES is super outdated and also NTLM is super outdated,
eliminating the warnings for OpenSSL 3.0 is still a step in the right
direction and using the correct APIs. We cheat a bit by using 3DES instead
of DES to avoid needing legacy provider for DES encryption for now.

Patch v4: add unit test, use 3DES to avoid legacy provider for now

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Max Fillinger <maximilian.fillinger@foxcrypto.com>
Message-Id: <20211029111109.2003101-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg23078.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>