.Net: C# package cleanup

[markwallace-microsoft]

Review C# package a determine if meta-namespaces can be created to make developer experience similar (anything else) All non GA packages should have a disposition i.e., graduate, obsolete/replace, redesign

• Plugins.Core package

  • [x] Revise experimental APIs and remove experimental attribute - https://github.com/microsoft/semantic-kernel/pull/11906
  • [x] Revise public API surface of Graduate Code Interpreter
  • [x] Graduate the package from alpha to preview - https://github.com/microsoft/semantic-kernel/pull/11950
  • ~[ ] Enable package validation after the next SK release - 1.50~

• OpenApi package

  • [x] Revise experimental APIs and update as needed - https://github.com/microsoft/semantic-kernel/pull/11745

• PromptTemplates.Liquid

  • [x] Revise experimental APIs and update as needed
  • [x] Graduate the package - https://github.com/microsoft/semantic-kernel/pull/11716
  • [x] Enable package validation after the next SK release - 1.49

• Functions.Markdown

  • [x] Add migration guide
  • [x] Remove from SK repo

• Planners

  • [x] Stop publishing them - https://github.com/microsoft/semantic-kernel/pull/11741
  • [ ] Remove from SK repo
  • [ ] Update documentation after python and java are ready

• [ ] Graduate Bing and Google TextSearch

• [ ] Remove obsolete packages: Planners, Orchestration Flow, Document, gRPC, MS Graph, ...