This change is to add Sdk.props and Sdk.targets of Microsoft.Docker.Sdk
into CLI. This unblocks the scenario where a VS solution contains a few
.NET Core projects as well as a docker-compose.dcproj project and people
want to build the solution from command line with .NET Core CLI. With
the Sdk.props and Sdk.targets being present in CLI, building
docker-compose.dcproj becomes no-op so it won't block building the other
.NET Core projects.
