Set up observer queries in didFinishLaunchingWithOptions to align with Apples recommendations

[robertherber]

To comply with Apple recommendations and to prevent any race conditions that might arise from initialising it later, as is the case now.

There are two parts to this:

• Document, based on Apple docs, how to add this to didFinishLaunchingWithOptions for Bare React Native apps.
• Add a config plugin for this so it works with Expo Managed Workflow.