Extends Jordan's Windows PR to support all courses

This extends support to Windows agents for all three courses.

* Install Chocolatey and set it as the default provider for all packages
  on the Windows platform.
* Uses Chocolatey to install git via the standard `puppetlabs/git` module.
    * I have a PR in to make this less noisy on Windows.
      puppetlabs/puppetlabs-git#41
* Configures W32Time to keep the VM's time synced.
* Installs Hexchat and configures it similarly to Irssi (practitioner)
* Updates our classroom_vm_version fact to work on Windows.
* Explicitly disables `source_permissions`
* Installs `poshgit`

## Note: This does not work offline yet.

Manually tested on all three ILT classroom environments. A previous
version of this was tested by @jolshevski and @gsarjeant in the
classroom.