Min/Max for weekly graphs in CnMaestro

The average throughput graphs are kind of useless at the "one week" level.  Even at lower resolutions such as 24 hours a lot of accuracy is lost with just the average throughput.  Would be nice to also see the min/max values at each point in the graphs to see the variance.  Think "smokeping".

https://oss.oetiker.ch/smokeping/doc/reading.en.html for an example of what this looks like.

Bump!  Averages only tell half the story!