Add on-short-runway signal and remaining-distance signal during RTO

* Added on-short-runway signal
* Allow on(-short)-runway anywhere on runway instead of just within 600 meters of the start
* on-short-runway is used to display something like "On runway 24, 2500 meter remaining" if remaining distance (because runway is short for example) is less than 3000 meter
* Set takeoff_config.nominal_distance_takeoff_m to the takeoff distance you usually need. By default it is 3000 meter

* Added remaining-distance signal during RTO. Required conditions:
    * Groundspeed must be at least 40 knots and 7 knots below the maximum attained groundspeed
    * Aircraft must be past 50 % of runway