Extension - GeoDatum Headers as of GPS Datum headers HFALG and HFALP

[mreinart]

according to FAI Sporting Code 2021 0.9.0 - 3.2.3 & 3.4 - - 3.2.3 & 3.4
https://www.fai.org/sites/default/files/civl/documents/sporting_code_s7_h_-_civl_flight_recorder_specification_2021_v0.9.0.pdf

HFALGALTGPS:GEO
HFALPALTPRESSURE:ISA