cli: add improved pool statistics
cli: add improved pool statistics

CLI now shows number of total / used / free prefix as per #528.

Part of #528.

SpriteLink/NIPAP,ettrig/NIPAP,garberg/NIPAP,SoundGoof/NIPAP,plajjan/NIPAP,garberg/NIPAP,bbaja42/NIPAP,plajjan/NIPAP,bbaja42/NIPAP,garberg/NIPAP,garberg/NIPAP,fredsod/NIPAP,fredsod/NIPAP,ettrig/NIPAP,bbaja42/NIPAP,SoundGoof/NIPAP,SoundGoof/NIPAP,fredsod/NIPAP,fredsod/NIPAP,plajjan/NIPAP,SpriteLink/NIPAP,ettrig/NIPAP,ettrig/NIPAP,bbaja42/NIPAP,SoundGoof/NIPAP,ettrig/NIPAP,SpriteLink/NIPAP,plajjan/NIPAP,fredsod/NIPAP,SpriteLink/NIPAP,SoundGoof/NIPAP,bbaja42/NIPAP,fredsod/NIPAP,SoundGoof/NIPAP,garberg/NIPAP,SpriteLink/NIPAP,garberg/NIPAP,ettrig/NIPAP,bbaja42/NIPAP,plajjan/NIPAP,SpriteLink/NIPAP,plajjan/NIPAP