Rename ncp-ciphers to data-ciphers

Rename ncp-ciphers to data-ciphers

The change in name signals that data-ciphers is the preferred way to
configure data channel (and not --cipher). The data prefix is chosen
to avoid ambiguity and make it distinct from tls-cipher for the TLS
ciphers.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Steffan Karger <steffan.karger@foxcrypto.com>
Message-Id: <20200717134739.21168-8-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg20444.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>