src: add openssl-system-ca-path configure option

The motivation for this commit is that we need to specify system CA
certificates when building node. While we are aware of the environment
variable NODE_EXTRA_CA_CERTS this is not a great solution as we build
an RPM and we also don't want users to be able to unset them.

The suggestion is to add a configure time property like this:

--openssl-system-ca-path=OPENSSL_SYSTEM_CA_PATH
             Use the specified path to system CA (PEM format) in
             addition to the OpenSSL supplied CA store or compiled-
             in Mozilla CA copy.

Usage example:
$ ./configure --openssl-system-ca-path=/etc/pki/tls/certs/ca-bundle.crt

This would add the specified CA certificates in addition to the ones
already being used.

PR-URL: https://github.com/nodejs/node/pull/16790


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>