Allow unicode search string in --cryptoapicert option

Allow unicode search string in --cryptoapicert option

Currently when the certificate is specified as "SUBJ:foo", the
string foo is assumed to be ascii. Change that and interpret
it as utf-8, convert to a wide string, and flag it as unicode
in CertFindCertifcateInStore().

Signed-off-by: Selva Nair <selva.nair@gmail.com>
Acked-by: Lev Stipakov <lstipakov@gmail.com>
Message-Id: <1581519967-16950-2-git-send-email-selva.nair@gmail.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg19405.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit aa6affe6df811db11577847366a569def0a3e314)