https://support.pingcap.com/hc/en-us/articles/360050038113-Create-TLS-Certificates-Using-CFSSL
https://rob-blackbourn.medium.com/how-to-use-cfssl-to-create-self-signed-certificates-d55f76ba5781
https://serverfault.com/questions/1004717/cfssl-to-start-with-intermediate-certificate