aktualizr-lite: Add a "list" command
aktualizr-lite: Add a "list" command

A simple command to list the updates available to a particular
device.

Signed-off-by: Andy Doan <e3579b1e47f273529f0f929453e939a68ede9fd1@foundries.io>

advancedtelematic/aktualizr,advancedtelematic/aktualizr,advancedtelematic/sota_client_cpp,advancedtelematic/aktualizr,advancedtelematic/sota_client_cpp,advancedtelematic/aktualizr