Data Model Improvement

[vjkoskela]

The ClusterAggregator data model is now independent from the TsdAggregator/MetricsAggregatorDaemon data models. Design decisions that were being made to support the combined data model should be re-evaluated. In particular, any decision should address the structure of the data with respect AggregatedData versus PeriodicData and which (if either) is most applicable to ClusterAggregator.

Regardless of which way the data model design evolves the following classes at least need to be considered in the refactoring. They currently use and seem to rely on deprecated methods in AggregatedData.

• PeriodicStatisticsActor
• PeriodMetrics
• BookkeeperPersistence
• Emitter
• AggMessageExtractor