Implement peer-fingerprint to check fingerprint of peer certificate

Implement peer-fingerprint to check fingerprint of peer certificate

This option allows to pin one or more more peer certificates. It also
prepares for doing TLS authentication without a CA and just
self-signed certificates.

Patch V2: Allow peer-fingerprint to be specified multiple times
          to allow multiple peers without needing to use inline
          syntax. (e.g. on command line).

Patch V3: rebase on v3 of 1/4, reword message of verify-hash and
          peer-fingerpring incompatibility

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Antonio Quartulli <antonio@openvpn.net>
Message-Id: <20210321143353.2677-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/search?l=mid&q=20210321143353.2677-1-arne@rfc2549.org
Signed-off-by: Gert Doering <gert@greenie.muc.de>