Create Microsoft.IO.Redist (dotnet/corefxdotnet/coreclr#31679)

Create Microsoft.IO.Redist (dotnet/corefxdotnet/coreclr#31679)

* Create Microsoft.Internal.IO

Includes all of Path, Directory, *Info, etc. from System.IO with targets of NetFX 4.6.1 and NetCore 2.1.

* Tweaks / minor fixes

* Remove netstandard build.

* Add package

Update to build for 4.7.2 only

* Rename folder to prepare for project rename

* Change the name to Microsoft.IO.Redist

* Namespace tweaks

* Use open key, tweak references

* More tweaks on feedback

Also grab latest build tools for 4.7.x RIDs

Signed-off-by: dotnet-bot <dotnet-bot@microsoft.com>
Commit migrated from https://github.com/dotnet/coreclr/commit/4ccd7a52827a9078b35e167bea488b3389538e92