feat: Platform runtime helper

[mcNets]

GitHub Issue (If applicable): closes #11545

PR Type

What kind of change does this PR introduce?

• Feature

What is the current behavior?

You have to use conditionals to knot the current platform runtime.

What is the new behavior?

You can use RuntimeHelper.CurrentPlatform enumeration.

PR Checklist

Please check if your PR fulfills the following requirements:

• Docs have been added/updated which fit documentation template (for bug fixes / features)
• Unit Tests and/or UI Tests for the changes have been added (for bug fixes / features) (if applicable)
• Validated PR Screenshots Compare Test Run results.
• Contains NO breaking changes
• Associated with an issue (GitHub or internal) and uses the automatic close keywords.
• Commits must be following the Conventional Commits specification.

Other information

Follow this conversation:
#18432 (reply in thread)

I've had some issues with the filtered solutions, I've had been able to test it in Skia only.

Please, someone else should check the other platforms.

Internal Issue (If applicable):
#11545

[Youssef1313]

SkiaIslands?

[spouliot]

When\where\how would Skia* (e.g. SkiaMacOS) be returned ?

There's no code to allow to set it (from the host) since it's returned from a method. An internal Set... method (only for __SKIA__ could be used by the different hosts).

Also if Skia* values are returned when would the lone Skia value be returned ?

You might want to add an extension method, on the enum, like IsSkia() to make it easier to detect all Skia-based platforms (and remove Skia).