Experimental Feature to add Temp: drive

[SteveL-MSFT]

PR Summary

Adds Experimental Feature called PSTempDrive that, if enabled, creates a PSDrive called Temp: that maps to [System.IO.Path]::GetTempPath().

PR Context

This enables cross platform way to easily access your temp folder since the env var is different across Windows, Linux, and macOS. Also makes it easier to write temp files in cases like Azure Functions where you can't write to the current working directory. Since this is a direct mapping to the user's temp path, there is no auto cleanup by PowerShell.

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[daxian-dbw]

LGTM.

[iSazonov]

What CL- label we need to assign?

[adityapatwardhan]

Just created a label CL-Experimental and attached to the PR.