[PATCH] Support loading server certificate from HW token

[Пичулин Дмитрий Николаевич]

I support the base idea to load certificates from engines but CMD_LOAD_CERT_CTRL ('LOAD_CERT_CTRL') seems not defined in openssl, it is an engine specific functionality. Is that the only way?

And secondly, i can not imagine that you can not get a certificate from your hardware prior nginx run, because the certificate information is always open. So this new functionality is not a must, but a useful one.