core: Add sending SCHEMA to cloud
core: Add sending SCHEMA to cloud

This patch adds the logic to receive the KNOT configuration message
and sends the JSON schema supported by the KNOT device.

CESARBR/knot-service-source,CESARBR/knot-service-source,CESARBR/knot-service-source,CESARBR/knot-service-source,CESARBR/knot-service-source