Mark the old `Microsoft.DSC/PowerShell` and `Microsoft.Windows/WindowsPowerShell` adapters as deprecated

[SteveL-MSFT]

Summary of the new feature / enhancement

Add a warning message when either of these two adapters are used and point to this issue. These adapters have been replaced by the new Microsoft.Adapters/PowerShell and Microsoft.Adapters/WindowsPowerShell adapters as we move away from the nested config model for adapters. Docs need to be updated to use adapted resources directly instead of wrapping them in a nested config.

Basically, users should not use this syntax:

$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
resources:
- name: Use class PowerShell resources
  type: Microsoft.DSC/PowerShell
  properties:
    resources:
    - name: PowerShell 7 Preview
      type: Microsoft.WinGet.DSC/WinGetPackage
      properties:
        Id: Microsoft.PowerShell.Preview

and instead change to:

$schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
resources:
- name: PowerShell 7 Preview
  type: Microsoft.WinGet.DSC/WinGetPackage
  properties:
    Id: Microsoft.PowerShell.Preview

Proposed technical implementation details (optional)

Add warning message that these are deprecated in 3.2
Consider formal removal in 4.0 release since this is a breaking change