tls-crypt-v2: add specification to doc/

tls-crypt-v2: add specification to doc/

This is a preliminary description of tls-crypt-v2.  It should give a good
impression about the reasoning and design behind tls-crypt-v2, but might
need some polishing and updating.

Signed-off-by: Steffan Karger <steffan.karger@fox-it.com>
Acked-by: Antonio Quartulli <antonio@openvpn.net>
Message-Id: <1540208715-14044-1-git-send-email-steffan.karger@fox-it.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg17788.html
Signed-off-by: David Sommerseth <davids@openvpn.net>