feat(conf): use openssl to detect system ca-certs path

[bungle]

Summary

Previously the code ran through these paths:

• "/etc/ssl/certs/ca-certificates.crt", -- Debian/Ubuntu/Gentoo
• "/etc/pki/tls/certs/ca-bundle.crt", -- Fedora/RHEL 6
• "/etc/ssl/ca-bundle.pem", -- OpenSUSE
• "/etc/pki/tls/cacert.pem", -- OpenELEC
• "/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem", -- CentOS/RHEL 7
• "/etc/ssl/cert.pem", -- OpenBSD, Alpine

when trying to find system ca-file.

The commit here asks openssl about it and tries from there first.

[bungle]

Alternatively we could make openssl the fallback rather than first priority.