Add support for Server 2025

[MichaelSimons]

New Windows Release

Windows version: Server 2025

Related to dotnet/core#9374

Main Branch Tasks

1. • Ensure a "New Windows Release" issue exists for docker-tools repo
2. • Copy the Dockerfiles of the most recent published Windows version for all supported .NET versions and place them in a version-specific folder under their respective variants (runtime, aspnet, sdk)
3. • Modify the Dockerfile templates if there are any specific changes needed that are related to the new Windows version
4. • Update manifest.json to reference the new set of Dockerfiles with the appropriate tags
5. • Update the test data to include the new Windows version
6. • Update the tags metadata templates to include the new Windows version
7. • Run the command to update the READMEs: .\eng\readme-templates\Get-GeneratedReadmes.ps1
8. • Run the command to update the image size baseline file: .\tests\performance\Validate-ImageSize.ps1 -UpdateBaselines
9. • Inspect generated changes for correctness
10. • Test the images
      1. • Create a local VM of the new Windows version
      2. • Clone this repo with the above changes onto the VM
      3. • Run .\build-and-test.ps1 -OS nanoserver-<VERSION> to build and test your changes for Nano Server
      4. • Run .\build-and-test.ps1 -OS windowsservercore-<VERSION> to build and test your changes for Windows Server Core
11. • Create PR
12. • Get PR signoff
13. • Merge PR and build/publish as part of the main branch release process for the next .NET release
14. • Create an announcement (example: Nano Server, version 20H2)
15. • Update the samples to reference the new Windows version:
      • Nano Server and Windows Server Core sample Dockerfiles
      • manifest.samples.json

Nightly Branch Tasks

• Merge these changes to the nightly branch as part of the nightly branch release process for the next .NET release.