Total Time vs Billable Time

We've added the ability to distinguish between total time and billable time separately, with billable time never exceeding total time. 

This distinction will help provide firms insights with the two data points and the valuable conversation to be had when they are different.

A few use cases we wanted to support:
-     giving the timekeeper credit for actual hours worked but still charging the customer for less time
-     measuring the difference between the two, showing "evaporation" of potential funds not collected on