Currently, the balancer's mode can either be set to 'full' or 'off'. We will soon be adding two new balancer modes ('unshardedOnly' and 'shardedOnly'), and we would like users to be able to check and change the balancer mode while the balancer is disabled. Therefore, we need to change the off setting to no longer be a mode of the balancer, but a separate field which can be changed independently of the mode.

This ticket should include updating the commands that set the balancer mode. It should also modify the commands that report the balancer settings to include both the mode and whether or not the balancer is enabled.