* remove sources.props and use NuGet.config. Source.props is only necessary for products that bulid in ProdCon, which Blazor does not
* Remove code signing glue code. This is part of KoreBuild now
* Update SDK to 2.1.400
* Update certificate names used for code-signing to use SHA2
* Change project layout to prepare for upcoming Arcade changes
* Add signtool config file to configure OPC, NuGet, and Authenticode signing
* Fix a bug when BaseIntermediateOutputPath is set to an absolute path
Nate McMaster
Steve Sanderson
Ryan Nowak
Nate McMaster