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

從現有的 Azure Pipelines 驗證建置和 AppVeyor 的建置組態開始，這些是 issue 中指定的進入點。追蹤 NuGet 套件的建立方式，並找出發佈至 Azure Artifacts 和 nuget.org 的步驟。完成的標準是 Azure Pipelines 建置並儲存套件，同時由獨立的 release pipeline 將其發佈至 nuget.org。