Arming and actuator state telemetry

[linguini1]

The hybrid communication specification requires that arming states and actuator states be sent as telemetry packets whenever a change to them occurs. This needs to be implemented in the pad server.

In addition, the pad server implementation should broadcast states periodically on a timer to cover scenarios where:

• There are lost packets
• The connection is momentarily interrupted
• New telemetry clients join the multicast group and need to be informed of the current state

[bskdany]

This issue is blocked by #10