Revamp Getting Started Experience

[GregoryComer]

📚 The doc issue

The current Getting Started experience in the documentation leaves a lot to be desired. There are a few major issues I'd like to solve:

1. Documentation is focused on C++ APIs and building from source. Provide dedicated paths for Android, iOS, and native/C++ runtime.
2. Android and iOS users don't need to build from source for common use cases. We should ideally cover downloading pre-built binaries in the getting started section. The information is currently somewhat buried in the docs. We should also split out information on building from source.

Suggest a potential alternative/fix

No response

cc @mergennachin @byjlw

[byjlw]

Yeah, it's the right thing to do. Next step in that direction is building a navigation map. Are you able to draft up one @GregoryComer?

[mergennachin]

#8179

[GregoryComer]

Updated getting started flow is merged in #8638