[telemetry] new periodic telemetry system

- only FW currently, rotorcraft coming soon
- compared to before:
 - no macros (easier to debug)
 - the default channel/device cannot be set for all the messages at the
   same time (it will be possible when we finally replace messages
   macros and define proper C struct for that)
 - the register function only register for a single process (not
   possible to reuse the function for an other process unless you
   explicitely register for it)
[telemetry] adapt rotorcraft to new telemetry system