ZEN-16442 - Improve indexFully synchronization, add timers, add summary_event.closed_status, batch dedups by fingerprint_hash

[kindkid]

• While adding timers, the introduction of the Counters interface was necessary to break cycles going through StatisticsServiceImpl. Trying to simply add Timed annotations resulted in spring framework errors.
• Adding summary_event.closed_status allows us to write queries and use composite indexes for much better query performance when there are lots of closed/aged/cleared events in the event_summary table.
• When a large portion of the events map to a small handful of fingerprint_hash values (lots of deduping), zep's ability to handle events pulled from rabbitmq suffered dramatically due to the transactions becoming serialized behind a "SELECT ... FROM event_summary ... FOR UPDATE" by fingerprint_hash. Batching the incoming events by fingerprint_hash for events that (may) need deduping improves performance.