.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

  • Revise experimental APIs and remove experimental attribute - .Net: Remove the experimental attribute from the core plugins #11906
  • Revise public API surface of Graduate Code Interpreter
  • Graduate the package from alpha to preview - .Net: Graduate Plugins.Core package from 'alpha' to 'preview'  #11950
  • [ ] Enable package validation after the next SK release - 1.50

• OpenApi package

  • Revise experimental APIs and update as needed - .Net: Remove the experimental attribute from stable openapi api #11745

• PromptTemplates.Liquid

  • Revise experimental APIs and update as needed
  • Graduate the package - .Net: Graduate Microsoft.SemanticKernel.PromptTemplates.Liquid package #11716
  • Enable package validation after the next SK release - 1.49

• Functions.Markdown

  • Add migration guide
  • Remove from SK repo

• Planners

  • [.Net] Stop publishing them - .Net: Obsolete SK planners #11741
  • [.Net] Remove from SK repo - .Net: Remove planners #12399
  • [Java] Java: Remove SK planners #12401
  • [Python] Python: Remove SK planners #12400
  • Remove documentation after python and java are ready

• Graduate Bing and Google TextSearch

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