Adding finer granularity of timers to HttpMetricsIngestionHandler

Added finer granularity of timers to HttpMetricsIngestionHandler to track different times of processing json, sending messages and persisting. 

* Check to see if anything else needs to be instrumented
* Check to see if the .time() method has been called in the right place so that it does not track the time spent sitting in queues
* Check any style issues indentation etc