App Detail Page totals for running instances
* Corrected "averageTransaction" to "averageTransactionTime";
* Add totals row for average transaction time and average idle time (for running instances only)
* For dictionary keys that were reused in multiple places, make public static Strings to minimize run-time errors (by making them compile-time errors), add javadoc for clarification;
* Refactor duplicate code into ONE convenience method averageTimeStatisticOfActiveInstances()