Cleanup Opscode connection handling

The connection object or any of the headers can't be configured from
callers. This change removes legacy documentation stating the opposite
and simplifies the Kernel#open() method call. As none of the Faraday
connection headers are configurable, there is no need to pass them to
open().
Follow redirects in cookbook archive requests

The open-uri implementation doesn't allow redirects from http:// to
https:// locations. Therefore, open-uri got replaced with httpclient.
This library was chosen as it was already part of the dependency tree
(ridley -> winrm -> httpclient) and solves the problem without
introducing any overhead.