[DRAFT] Introducing the "Onboarding scenarios" folder to support the new "How-tos" node in our conceptual TOC

[MatchaMatch]

Description

The Windows docs team is currently experimenting with the introduction of a scenarios-oriented How-Tos node in our conceptual TOC:

Context and rationale are detailed in a design doc.

This PR includes the source code that supports the WIP "How to build a Hello World app" how-to, previewable here. Here's the accompanying PR for the how-to doc.

Target Release

n/a

Checklist

• Samples build and run using the Visual Studio versions listed in the Windows development docs.
• Samples build and run on all supported platforms (x64, x86, ARM64) and configurations (Debug, Release).
• Samples set the minimum supported OS version to Windows 10 version 1809.
• Samples build clean with no warnings or errors.
• [For new samples]: Samples have completed the sample guidelines checklist and follow standardization/naming guidelines.
• If I am onboarding a new feature, then I must have correctly setup a new CI pipeline for my feature with the correct triggers and path filters laid out in the "Onboarding Samples CI Pipeline for new feature" section in samples-guidelines.md.
• I have commented on my PR /azp run SamplesCI-<FeatureName> to have the CI build run on my branch for each of my FeatureName my PR is modifying. This must be done on the latest commit on the PR before merging to ensure the build is up to date and accurate. Warning: the PR will not block automatically if this is not run due to '/azp run' limitation on triggering more than 10 pipelines.

[MatchaMatch]

cc @asklar - this is a WIP but I wanted to get this on your radar sooner rather than later in case you have any feedback on the broad strokes (of either the sample or the accompanying how-to linked from the PR description)🙏

[MatchaMatch]

I need to review the Samples repo guidelines to determine if/how PII like this should be handled (ideally removed).

[MatchaMatch]

I need to review the Samples repo guidelines and apply README templating (if it exists).

[asklar]

@codendone and @MikeHillberg to take a look