Add a new Windows Server 2016 folder which will have similar content to the Windows 10 folder. Upload the GPO and create a Nessus audit file.
Update New-PolicyDefinitions.ps1 to add Windows Server 2016. Perhaps add a Role or SystemRole property that can have 'Server' and 'Desktop' or 'Server','Desktop' (or 'Member Server, Domain Controller, Workstation' like Win32_OperatingSystem.ProductType) as values. $osVersion may need to be split into desktop and server versions.
Update GroupPolicy.psm1 to have 'Windows 10' and 'Windows Server 2016' as options for -PolicyNames argument. Maybe need to add a SystemRole argument.
Windows Server 2016 SHB was recently released. I need to add the GPOs and update the scripts that apply the GPOs.