Add more information on how to run the app on an emulator.

https://finp.github.io/aerogear/latest/getting-started.html#running-the-mobile-app-in-an-emulator

This page gets pulled from here so content for this can be loaded there

The linked task requires the removal of the `Doing Stuff` section so please remove this when you add the content required by this task.

Preferably link out to existing platform specific docs on how to do that if it exists. Use the platform tabbing format
Trello link