Need instructions for provisioning if you don't have FRAM

[terrillmoore]

Working with the Catena 4410 and 4420 is difficult.

The instructions currently don't mention that you need to have files catena-lorawan-provisioning/gk_lorawan_keys.project.cpp and catena-lorawan-provisioning/gk_lorawan_keys.4420.cpp. Only one file is used, depending on whether your project uses class object derived from Catena4410 or from Catena4420. There are two problems:

1. There's no guidance on setting up these files
2. Only one file should be needed, but both are currently required (due to the Arduino environment's "compile everything" philosophy). The one that isn't required for a given project should be empty.

Consider providing a repo that can be downloaded and configured using a bash script.

This was formerly mcci-catena/Catena-Sketches#2