Add performance metrics

Summary

Adds new metrics to the Runtime that exposes information that can be used to more clearly investigate performance.

More metrics for committed events and committed aggregate events
Metrics for total number of aggregate concurrency conflicts
Metrics for Event Handlers; registrations, number processed, failed and processing time
Metrics for registrations/initializations/starts of stream processors and the events they processed or failed to process per event processor kind
Metrics for the .NET Runtime