Add analytics base on Events

[QianSwirlds]

Basic Network Health Analytics Based on Events

1. Count Created Events Per time window
2. Count Reached Consensus Events Per time window
3. Count Created Events Per time window Per Node
4. Count Reached Consensus Events Per time window Per Node
5. Count of System & User Transactions in Reached Consensus Events Per time window Per Node
6. query for the min, median, and max latency (consensusTimestamp - timeCreated)for all events that reached consensus in a given time window, per node.
7. get the latency of events that reached consensus in a given time window

[QianSwirlds]

Added EventStreamAnalytics.java

1. Count Created Events Per time window
   long getCreatedEventsCount(long periodStartInNanos, long periodEndInNanos)

2. Count Reached Consensus Events Per time window
   getConsensusEventsCount(long periodStartInNanos, long periodEndInNanos)

3. Count Created Events Per time window Per Node
   long getCreatedEventsCountForNode(long periodStartInNanos, long periodEndInNanos, long nodeId)

4. Count Reached Consensus Events Per time window Per Node
   getConsensusEventsCountForNode(long periodStartInNanos, long periodEndInNanos, long nodeId)

5. Count of System & User Transactions in Reached Consensus Events Per time window Per Node
   long[] getSysAppTxsCountInConsensusEventsForNode(long periodStartInNanos, long periodEndInNanos, long nodeId)

6. query for the min, median, and max latency (consensusTimestamp - timeCreated)for all events that reached consensus in a given time window, per node.
   long[] getLatencyStatsForNode(long periodStartInNanos, long periodEndInNanos, long nodeId)

7. get the latency of events that reached consensus in a given time window
   long[] getLatencyStats(long periodStartInNanos, long periodEndInNanos)

[QianSwirlds]

closed by #17