framework/target: wait 20 sec for network to show up
framework/target: wait 20 sec for network to show up

Some targets need more than 5 seconds to re-connect to a wifi network
after disabling airplane mode. To fix that, poll for network up to 20
seconds and show a warning if unreachable.

lisatn/workload-automation,setrofim/workload-automation,lisatn/workload-automation,lisatn/workload-automation,ARM-software/workload-automation,ARM-software/workload-automation,lisatn/workload-automation,ARM-software/workload-automation,setrofim/workload-automation,setrofim/workload-automation,ARM-software/workload-automation,setrofim/workload-automation