req 2.4.1: Pool utilization

As a user I need to quickly be able to see the utilization % (per pool), and quickly identify pools that have very high utilization. This is often done with colors or other graphical indicators to make it easy to spot pools with high utilization with a quick visual scan.

1. For a given subnet and or pool, how many of the allocated addresses are currently assigned, and how many of these addresses are available for use? This is often graphically displayed with a visual indicator that permits me to quickly scan for highly-utilized subnets and pools.

This requirement does not include any alerts. See 2.4.2 (#48).