Make sure cert provider writes gateway URL file where expected
Make sure cert provider writes gateway URL file where expected

Write the gateway URL file to the default base path (/var/sota/import)
or the configured base path.

Signed-off-by: Stefan Agner <8bf81831f67286fff829779134e88c94b37210a1@toradex.com>

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