Detect Network beaconing via Intra-Request time delta patterns in Azure Sentinel

Thanks Tony Roth for reviewing detection and leaving the comment. Beaconing often happens at regular intervals although c2 networks/frameworks can change and add randomness to communication pattern, it is still good idea to monitor periodic communication from internal hosts to unknown public addresses. 

Some approaches were suggested to reduce false positives or filter the benign traffic such as tweaking timedelta/ percent beacon threshold, profiling network and segregating known destination IP ranges/registrant org. If you have any generic tuning recommendation, we would gladly accept via Pull Request to the sentinel repo.