Setup 唔難，但係好高機會睇漏，唔duplicate template
Reference
https://blogs.technet.microsoft.com/yungchou/2013/10/22/enterprise-pki-with-windows-server-2012-r2-active-directory-certificate-services-part-2-of-2/
http://www.tech-coffee.net/public-key-infrastructure-part-8-ocsp-responder/