feat: apple view filtering

[NathanWalker]

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• Tests for the changes are included - https://github.com/NativeScript/NativeScript/blob/master/tools/notes/WritingUnitTests.md.

What is the current behavior?

You could only scope/filter views by ios, android, or visionos.

What is the new behavior?

For cases where something should be shown on both ios and visionos, you can now surround views with:

<apple>Apple only content which shows on all available apple platforms, eg iOS and visionOS</apple>