doc/man: Mark compression options as deprecated

doc/man: Mark compression options as deprecated

Due to the VORACLE attack vector, compression in general is deprecated.
Make this clear in the man page.

Also remove an incorrect statement claiming --compress lzo is compatible
with --comp-lzo.  It is not, as --compress lzo uses a different
compression framing than --comp-lzo.

Signed-off-by: David Sommerseth <davids@openvpn.net>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20200716225338.611-6-davids@openvpn.net>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg20417.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>