add Import-Module ServerManager for win2012r2 PS commands

[devcfgc]

I've been testing all day on some win2012r2 machines:

• vagrant: I used this box MattHodge/Windows2012R2-WMF5-NOCM
• azure VM
  Also tested with Powershell:
• v 5.0
• v 5.1
  In all my tests I need to add the Import-Module ServerManager; for the correct execution of the commands otherwise, some Powershell commands won't work.

[vinzent]

what problem is fixed by this PR ?

[devcfgc]

I tested in windows server 2012 and in all cases, I needed to use Import-Module ServerManager; otherwise, I get an error that the module Get-WindowsFeature | Install-WindowsFeature | Uninstall-WindowsFeature couldn't be found. I don't have too much experience with porwershell but it seems that the \\system32\\WindowsPowershell\\v1.0\\powershell.exe can't use those commands without importing the servermanager module

[vinzent]

https://technet.microsoft.com/en-us/library/ff476071.aspx indicates the import is necessary for (Add|Get|Remove)-WindowsFeature cmdlets.

[vinzent]

@devcfgc , thank you for your contribution !