Consolidate Steeltoe Packages Names

[TimHess]

Over the last several releases of .NET (Core), Microsoft has moved towards ASP.NET Core and several key .NET feature areas (like Configuration, Dependency Injection and Logging) being included in the runtime, removing the NuGet references that we were trying to avoid pulling in unless necessary. As such, there's no longer a solid reason for the Base/Core suffix naming convention that Steeltoe has used since version 2.0.

Steeltoe 4.0 will look to consolidate packages in order to streamline package naming and dependency trees.