[Feature Request]: Ability to configure PSRepository on a system-wide level

It would be great if there was a way to register a PSRepository on the system-wide level, so that if configured once, it would work for all the users on a particular system.

Expected Behavior

Register-PSRepository should have a -Scope parameter added, to control whether a particular PSRepository needs to be registered for just the current user of for the whole system (similar to the behavior of Execution Policy). It would also be great to have an extra scope option, that would register PSRepository just for the current session (like mentioned in PowerShell/PowerShellGet#65)

Apart from the Register-PSRepository, the remaining set of the *-PSRepository cmdlets should also have the -Scope parameter. Set-PSRepository and Unregister-PSRepository cmdlets should require admin privileges to work against system-wide PSRepository settings and 'Get-PSRepository' cmdlet should not require admin privileges at all.

Current Behavior

Currently Register-PSRepository only works for the user that is executing the cmdlet.

Context

Having an ability to register PSRepository on a system-wide level would allow us to pre-configure our internal Repositories in the Virtual Machine templates, thus making the provisioning process much simpler.

Additionally, that would simplify maintaining existing PSRepository configurations in a consistent fashion across all our systems.

Your Environment

PS C:\Users> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      5.1.15063.726
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.15063.726
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1


PS C:\Users>
PS C:\Users> Get-Module

ModuleType Version    Name                                ExportedCommands
---------- -------    ----                                ----------------
Manifest   3.1.0.0    Microsoft.PowerShell.Utility        {Add-Member, Add-Type, Clear-Variable, Compare-Object...}
Script     1.2        PSReadline                          {Get-PSReadlineKeyHandler, Get-PSReadlineOption, Remove-PS...


PS C:\Users>
PS C:\Users> Get-Module -ListAvailable PowerShellGet,PackageManagement


    Directory: C:\Program Files\WindowsPowerShell\Modules


ModuleType Version    Name                                ExportedCommands
---------- -------    ----                                ----------------
Script     1.1.7.0    PackageManagement                   {Find-Package, Get-Package, Get-PackageProvider, Get-Packa...
Script     1.1.1.0    PackageManagement                   {Find-Package, Get-Package, Get-PackageProvider, Get-Packa...
Binary     1.0.0.1    PackageManagement                   {Find-Package, Get-Package, Get-PackageProvider, Get-Packa...
Script     1.6.0      PowerShellGet                       {Install-Module, Find-Module, Save-Module, Update-Module...}
Script     1.1.2.0    PowerShellGet                       {Install-Module, Find-Module, Save-Module, Update-Module...}
Script     1.0.0.1    PowerShellGet                       {Install-Module, Find-Module, Save-Module, Update-Module...}


    Directory: C:\Program Files (x86)\WindowsPowerShell\Modules


ModuleType Version    Name                                ExportedCommands
---------- -------    ----                                ----------------
Binary     1.0.0.1    PackageManagement                   {Find-Package, Get-Package, Get-PackageProvider, Get-Packa...
Script     1.0.0.1    PowerShellGet                       {Install-Module, Find-Module, Save-Module, Update-Module...}


PS C:\Users>
PS C:\Users> Get-PackageProvider

Name                     Version          DynamicOptions
----                     -------          --------------
msi                      3.0.0.0          AdditionalArguments
msu                      3.0.0.0
NuGet                    2.8.5.210        Destination, ExcludeVersion, Scope, SkipDependencies, Headers, FilterOnTag...
PowerShellGet            1.6.0.0          PackageManagementProvider, Type, Scope, AllowClobber, SkipPublisherCheck, ...
Programs                 3.0.0.0          IncludeWindowsInstaller, IncludeSystemComponent


PS C:\Users> Get-PackageProvider -ListAvailable

Name                     Version          DynamicOptions
----                     -------          --------------
msi                      3.0.0.0          AdditionalArguments
msu                      3.0.0.0
nuget                    2.8.5.208
NuGet                    2.8.5.210        Destination, ExcludeVersion, Scope, SkipDependencies, Headers, FilterOnTag...
NuGetProvider            2.8.5.208
PowerShellGet            1.6.0.0          PackageManagementProvider, Type, Scope, AllowClobber, SkipPublisherCheck, ...
PowerShellGet            1.1.2.0
PowerShellGet            1.0.0.1
Programs                 3.0.0.0          IncludeWindowsInstaller, IncludeSystemComponent