Mark language packs as obsolete

[Tratcher]

With the build infrastructure changes introduced for 4.2.1 the language satellite packages are no longer produced. Consider marking the packages as obsolete on nuget so it's clear to people that we are no longer publishing them.
https://www.nuget.org/packages/Microsoft.Owin.zh-Hans/

@adityamandaleeka @mkArtakMSFT We could consider this as part of the ongoing effort to mark old packages.