Json support to set Firebase Remote Configs defaults

## What feature would you like to see?

Would be very usefull to have a simple way to export the firebase remote config fields to a json/xml and import them into another project/default values file.

Today in order to do that we must config a sample project (available here) but this project isnt able to generate de default values file.
Would be very usefull to have a simple way to do that, i have several remote config fields and app wont work without them. so on first run user must wait a few seconds (depending on his internet) to load the remote config constants) would be very nice if i could take a snapshot of the remote config values and pack it inside the apk in order to make first run faster