Reduce external Windows gem dependencies - Phase 1

Remove the win32 gems from the puppet-agent package / as a gem dependency, and rewrite code where appropriate, since:

• these gems have caused accidental breakage in CI
• they have been known to cause issues with our UTF-8 support
• we're unclear about future support
• we don't control the release cadence / cycle
• we have the in-house expertise to maintain code as needed for the facilities these gems provide - and in some cases we don't need much of what's in the gems
• our release process becomes much simpler if limited amount of supporting code becomes part of the Puppet repo rather than needing to maintain gem patches for builds / gem mirrors for tests / etc