Add samples projects to a solution

[twsouthwick]

This starts the process of refactoring the samples to not be inline.
Instead, this change creates a solution that the samples are added to in
order to validate they are correct (and enable refactoring much easier
in the future). This adds a script in the samples directory that helps
scaffold out a new sample project.

[learn-build-service-prod]

Learn Build status updates of commit d781d7d:

✅ Validation status: passed

File	Status	Preview URL	Details
.github/workflows/samples.yml	✅Succeeded
docs/how-to-accept-all-revisions-in-a-word-processing-document.md	✅Succeeded
docs/how-to-add-a-comment-to-a-slide-in-a-presentation.md	✅Succeeded
samples/add-sample.ps1	✅Succeeded
samples/Directory.Build.props	✅Succeeded
samples/Directory.Build.targets	✅Succeeded
samples/migrate-sample.ps1	✅Succeeded
samples/presentation/add_comment/cs/add_comment_cs.csproj	✅Succeeded
samples/presentation/add_comment/cs/Program.cs	✅Succeeded
samples/presentation/add_comment/vb/add_comment_vb.vbproj	✅Succeeded
samples/presentation/add_comment/vb/Program.vb	✅Succeeded
samples/README.md	✅Succeeded
samples/samples.sln	✅Succeeded
samples/tools/migrator/migrator.csproj	✅Succeeded
samples/tools/migrator/Program.cs	✅Succeeded
samples/word/accept_all_revisions/cs/accept_all_revisions_cs.csproj	✅Succeeded
samples/word/accept_all_revisions/cs/Program.cs	✅Succeeded
samples/word/accept_all_revisions/vb/accept_all_revisions_vb.vbproj	✅Succeeded
samples/word/accept_all_revisions/vb/Program.vb	✅Succeeded

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel