(#8408/8409) Add a Windows ADSI helper module

This module (Puppet::Util::ADSI) provides access to Active Directory Services
Interfaces, using win32ole. The base module has methods for generating resource
URIs and connecting to ADSI.

It also provides classes Puppet::Util::ADSI::User and Puppet::Util::ADSI::Group
for managing Active Directory users and groups, along with their properties and
group memberships. This will be used to implement the Windows ADSI user and
group providers.

Based on work by: Joel Rosario <joel.r@.internal.directi.com>
Based on work by: Cameron Thomas <cameron@puppetlabs.com>
Reviewed-By: Matt Robinson <matt@puppetlabs.com>