Improve start and landing detection

[MaxBaex]

• start flight data logging only when e.g. vtas > 60kmh (test via simulated pitot pressure)
• stop flight logging when vGround & vTas < 40kmh for at least 1 minutes to also capture the landing and to be robust for high wind wave or acrobatic flight conditions.
• After landing: close the flight data recording file, write latest sensor calibration values to the eeprom and dump to sd card.
• Shall there be a feature to enable continuous logging via a sd-card configuration file?

[degeflija]

Basically, this is solved in AD57_FrontEnd. AD57 needs such info accordingly.
If such info were available by sensor, I could lean the AD57 code.