Windows Server, version 1709 no longer Supported by .NET Framework

# Windows Server, version 1709 no longer Supported by .NET Framework

Windows Server, version 1709 is no longer supported. As a result, this version of Windows is no longer supported by the .NET Team and we will no longer produce .NET Framework container images for those Windows versions.

Support statements:

* [Currently supported .NET Framework Docker images](https://hub.docker.com/_/microsoft-dotnet-framework)
* [.NET Framework Support Policy](https://dotnet.microsoft.com/platform/support/policy/dotnet-framework)
* [Products Reaching End of Support for 2019](https://support.microsoft.com/en-us/help/4316957/products-reaching-end-of-support-for-2019)

## Discussion
Please share your thoughts on this change and see what others are saying at:

* [dotnet-framework-docker #259](https://github.com/Microsoft/dotnet-framework-docker/issues/259)

## Details

Docker tags that contain `windowsservercore-1709` are no longer be produced. We will not delete existing images or those tags, however, they contain unsupported builds of Windows Server and .NET Framework.

## Pulling manifest tags

These changes also affect manifest tags (AKA “multi-arch tags“), such as `4.7.1`, and `4.7.2`. These are tags that are supported on multiple operating systems and versions, and do not contain the operating system in them. As a result of no longer producing new images for Windows Server, version 1709, manifest tags no longer include entries for Windows 10, version 1709, and Windows Server,version 1709. That means that .NET Core manifest tags are no longer usable on those Windows versions.

If you pull a manifest tag on one of the Windows versions described, you may get one of the following error messages:

* `a Windows version 10.0.17134-based image is incompatible with a 10.0.16299 host`
* `no matching manifest for windows/amd64 in the manifest list entries`
* `no matching manifest for unknown in the manifest list entries`

If you need to still use Windows Server, version 1709 images (even though they are no longer supported), you will need to use tags that include the Windows Server version (these are non-manifest tags), for example `mcr.microsoft.com/dotnet/framework/runtime:4.7.2-windowsservercore-1709` or `mcr.microsoft.com/dotnet/framework/sdk:4.7.2-windowsservercore-1709`.

No repository file, test, or code entry point is identified. Read the linked .NET Framework support policy, Docker image documentation, and dotnet-framework-docker issue #259; the announcement already states that Windows Server 1709 tags are no longer produced.

Written by the indexing model from the issue text.