Added parameters in hyper_v.pp to decide the tools to install

Hi,
I've added new parameters to *hyper_v.pp*:
* **ensure_powershell**: this one is used to specify if the feature *Hyper-V-PowerShell* will be installed. Defaults to *present*.
* **ensure_tools**: the same for the *Hyper-V-Tools* feature but defaulting to *absent*.

I think for compute nodes it makes sense to install the powershell module but not the tools as the best practice for hyper-v nodes seems to be using ServerCore installations.