Add finger() parameter to ignore CA verification

[ghost]

WebFinger forces HTTPS use but not necessarily CA verification. The RFC7033 referenced document on handling CA verification in TLS (RFC2818, https://tools.ietf.org/html/rfc2818) mentions that "Automated clients MAY provide a configuration setting that disables this check, but MUST provide a setting which enables it."

This is the configuration setting that disables such a check.