aktualizr-lite: Support using TLS keys
aktualizr-lite: Support using TLS keys

This is a bit of an edge case, but I've found it useful to run
devices in the lite mode, but to still restrict who can access
the tuf/treehub repos via TLS.

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

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