Use mavlink_msg_home_position to publish home position (instead of mavlink_msg_gps_global_origin)

[Consti10]

Current Behavior

mavlink_msg_gps_global_origin is used to publish the home position. I don't think this is the best fit though (it creates incompability with gcs that work with ardupilot)

Desired Behavior

INAV shall work just as well with gcs that are also used with ardupilot.

Suggested Solution

Replace mavlink_msg_gps_global_origin with mavlink_msg_home_position

Who does this impact? Who is this for?

All inav users using mavlink telemetry.

Additional context

#9072

[b14ckyy]

Moving to Discussion as change request

[sensei-hacker]

There is a subtle difference between the two values.

Safehomes and waypoint 255 bring up a question. Origin is of course the takeoff point, and the 0,0 point of the coordinate space. But should home_position be set to the current home (safehome, 255)? Or do we want it to mirror origin?