[radio_control] cleanup channel defines

- PPM: remove PPM_NB_CHANNEL define an always decode RADIO_CTL_NB (number of channels in radio.xml)
- PPM: the actually used/needed channels RADIO_CONTROL_NB_CHANNEL default to RADIO_CTL_NB but can be overwritten by user
  e.g. to use less channels for intermcu
- SBUS: only provide a default for RADIO_CONTROL_NB_CHANNEL
[radio_control] spektrum: copy only actually used channels to radio_control.values
[radio_control] error if RADIO_CONTROL_NB_CHANNEL > max available channels
[conf] Example that needs the RADIO_CONTROL_NB_CHANNEL
[stm32] spektrum: always decode up to 12 channels

but only copy RADIO_CONTROL_NB_CHANNEL to radio_control.values
[conf] outback airframes
move conf
removed bad airframes
handler = non-delayed call: call is now non-delayed
FBW compiles
AP compiles but does not link
cleanup
cleanup continued
[nav_airspeed] tune navigation airspeeds for diffent phases of the flightplan
remove obc features until it compiles
qnh -> air data