Implement functionality to enable winrm ntlm auth using encrypt/decrypt

This extends the ruby core sspi module and httpclient to support Encrypt/Decrypt data during negotiate. 
Ideal changes would be contributing to core ruby code and httpclient gem, which we will send out the pull request. 
This helps us successfully test the chef knife winrm over ntlm when basic auth is disabled on server and winrm/config/service AllowUnencrypted set to false. 

Fix would help us avoid workaround to enable basic - https://github.com/WinRb/WinRM#troubleshooting