Plane: support off-board terrain navigation #28537

Job	Run time
build (chibios, Durandal)	10m 4s
build (chibios, MatekF405)	18m 7s
build (chibios, KakuteF7)	17m 1s
build (chibios, MatekH743-bdshot)	9m 46s
build (chibios, Pixhawk1-1M)	16m 24s
build (chibios, MatekF405-CAN)	1m 56s
build (chibios, DrotekP3Pro)	1m 59s
build (chibios, Hitec-Airspeed)	4m 1s
build (chibios, f103-GPS)	3m 40s
build (disco, armhf)	6m 37s
	1h 29m 35s

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