Configure sshd-otp for FreeBSD bastion
Summary: Enable OPIE and Yubikeys OTP, but no stable password.
Test Plan: ssh -p 5022 -o PubkeyAuthentication=No ysul.nasqueron.org
Reviewers: dereckson
Reviewed By: dereckson
Differential Revision: https://devcentral.nasqueron.org/D1338