Top-level supervisor for reckon-gater

Supervision Tree

reckon_gater_sup (one_for_one) - reckon_gater_cluster_sup (rest_for_one) - reckon_gater_worker_registry - reckon_gater_cluster_monitor - reckon_gater_channel_sup (one_for_one) - 10x channel workers

Note: reckon_gater_api is a stateless API module, not a supervised process.