Support .NET Core SDK Portable Mode

[jamiewest]

I would like to be able to use the .NET Core SDK from a USB drive, this is already somewhat possible but there are still default folders created on the host system (.nuget, .dotnet, .templateengine, etc.). There is already some issues around this:

7569 - Request, able to config the location of ~/.dotnet and ~/.templateengine
4003 - Change default .nuget/package folder .NET Core

It would be nice to have an option, maybe in the dotnet-install script, to enable a -Portable option that would change the path for all directories used by the SDK to point to a single location (i.e. a USB .\data\ folder). This way full usage of the SDK would never touch the host file system.

The Dream Setup:

Use VS Code Portable with .NET Core SDK Portable living solely on a USB drive, and being able to move from computer to computer with a full dev environment on your key chain.

[leecow]

Issue moved to dotnet/cli #9853 via ZenHub