forward: get rid of useless declarations for actually static functions

forward: get rid of useless declarations for actually static functions

A bunch of functions defined in forward.c and declared in forward.h
are actually used only in forward.c.

For this very reason they don't need to be declared in forward.h at
all and can be defined as static.

Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Acked-by: Lev Stipakov <lstipakov@gmail.com>
Message-Id: <20210505231255.1880-1-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg22315.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>