Also changed GPS FactGroup values to use NaN appropriately to show
unavailable values.

altitudeAMSL and altitudeRelative do not need divide 1000，the unit is meter and float format。 can you use _handleGlobalPositionInt message for altitudeAMSL and altitudeRelative？ because _handleGlobalPositionInt is default 5Hz and _handleAltitude is 1Hz.

It's not desired to have automatic log streaming for several reasons:
- There's already SD logging (which is the case for the majority of the
  users)
- The link does not provide the necessary bandwidth (eg. wireless telemetry)

* Some code moved to Vehicle

* Moved from UAS
* Remove unused code

* Make MainToolbarIndicators reusable by other views
* Change to font based ratio sizing

This prevent the visibility change from trashing source setting