Use the ConnectivityTracker in Topology
return False to indicated switch has been failed successfully
more logging messages to ConnectivityTracker
Update Add/Remove Intent to use the ConnectivityTracker to update policies
log return value of executed events
Update fuzzer code

- fix issue with keeping track with reverse intents
- force the controllers to check their status, to change from starting to running state
- remove intent check capability should be only used if remove_intent_rate > 0
- Issue NOP event on initializing time
- more logging
Update all_controller_dead to return dead controller but not failed controllers