cfreader/[ini, json, yaml, binary, list] with tests!

Issue #784 leaves me wanting to get configfile under test. This PR extracts the file types into their own libraries with test coverage.
You can't do this because of this: https://github.com/baudehlo/Haraka/pull/785/files#diff-3cbca5576e2450b7c9164bbe9e1a8ee7R182

You're setting the value on a copy of the variable.