arch.sh: use binary repository for gazebo
arch.sh: use binary repository for gazebo

This makes installation a lot faster and less error prone.

krbeverx/Firmware,acfloria/Firmware,PX4/Firmware,PX4/Firmware,krbeverx/Firmware,acfloria/Firmware,PX4/Firmware,acfloria/Firmware,acfloria/Firmware,acfloria/Firmware,krbeverx/Firmware,acfloria/Firmware,krbeverx/Firmware,krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,PX4/Firmware,PX4/Firmware,krbeverx/Firmware,acfloria/Firmware