[ins] vf_extended: rename update_alt to update_z

this makes more sense as it is with z-down and vff_update_z_conf can be used for both vf_float and vf_extended_float
[ins] no baro update if vf_reset && !baro_initialized
[ins] gps_passthrough type for rotorcrafts
[rotorcraft] simple HITL by using ref as gps
[rotorcraft] gps_sim_hitl: set gps alt and hmsl

now the simple HITL should work with ins gps_passthrough