The commander used to consume the battery_status topic and write the
contents after some calculations into the system state. Instead, the
calculations now happen in library calls in systemlib/battery.
This moves the battery fields out of the vehicle_status message into the
battery_status topic.
This brought quite some changes in all modules that need battery
information. The current state is compiling but untested.
This is a cherry-pick of commit 8bd17a4b0cd9c1432cb57a9a80a215692f532370
in 3drobotics/PX4Firmware-solo
Conflicts:
src/drivers/batt_smbus/batt_smbus.cpp
src/drivers/drv_irlock.h
src/lib/ecl