I am thinking how we are going to support "3rd-party keyboard" with this property.
(Note that 3rd-party might be preloaded by our partner.)

Do you think we can do
 1. `appName`  => Use Gaia default domain, so the app origin would be "[appName].gaiamobile.org".
 2. `appOrigin`  => Use this as is for appOrigin.

BTW, the file might be referenced by FTU and settings at the same time, but they might not be able to access "app management API" to get the Gaia domain.
So maybe we need to generate the default layout definition files for FTU/settings app, based on this file?