build: store default/device packages in JSON

With this commit the `profiles.json` contain both the target specific
`default_packages` as well as the device specific `device_packages` as a
array of strings.

This information is required for downstream projects like the various
web-based interactive firmware generators.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Paul Spooren <mail@aparcar.org>

scripts/json_add_image_info.py

@@ -54,6 +54,7 @@ image_info = {
                     "sha256": image_hash,
                 }
             ],
+            "device_packages": getenv("DEVICE_PACKAGES").split(),
             "supported_devices": getenv("SUPPORTED_DEVICES").split(),
             "titles": get_titles(),
         }