tools: Add sending KNOT data
tools: Add sending KNOT data

This patch extends ktool to create the KNOT data message datagram and
send it to the gateway.

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