Azure Pipelines build and release pipeline

At present, we have a mix of build systems that I would like to unify.

1. Azure Pipelines for Linux, Windows and macOS.
2. Travis for Linux and macOS
3. Appveyor for Windows

I'd like to standardize around Azure Pipelines. At the moment, it's only doing a build for validation. I would like the build step to:

1. Create a nuget package (see AppVeyor's build configuration)
2. Upload that nuget package to Azure Artifacts

Then I'd like to have a separate release pipeline that will:

1. Take the nuget package from Azure Artifacts
2. Upload the nuget package to nuget.org

Comece com o build de validação existente do Azure Pipelines e a configuração de build do AppVeyor, que são os pontos de entrada nomeados na issue. Rastreie como o pacote NuGet é criado e identifique as etapas de publicação no Azure Artifacts e no nuget.org. Está concluído quando o Azure Pipelines compila e armazena o pacote, enquanto um pipeline de release separado o publica no nuget.org.