Add INS and GPS positions, set Vertical position source to GPS

[Williangalvani]

• Stop using barometer inside hull as a source of altitude
  • Switch to GPS by default → still not great, but at least trying to measure the right thing
• Set the known INS and GPS sensor locations in the BlueBoat hull
  • Improves motion estimation, which improves control performance
  • Center of control assumed as the center of the boat