Add better support for showing TLS 1.3 ciphersuites in --show-tls

Add better support for showing TLS 1.3 ciphersuites in --show-tls

--show-tls shows mixed TLS 1.3 and TLS 1.2 ciphers.  The listed ciphers
are only valid in either --tls-cipher or --tls-ciphersuites, but it's
not clear which is which. This is confusing and not really helpful.

This patch modifies show-tls to show separate lists for TLS 1.2 and
TLS 1.3.

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Steffan Karger <steffan.karger@fox-it.com>
Message-Id: <20181010153624.27957-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg17723.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit 7aeabadd69fca0071152c42d58fee0b565f01eb3)