Fix for PR #1398262 - when the node data points has huge difference in avg_bw some of the nodes are not getting displayed in scatter chart
1. converted all the parsed data values to bytes and used FormatByteAxis to autoscale to the right unit.
2. fixed all the scatter charts to reflect the dynamic Y axis unit
3. added destroy funtion for the infra storageNodes class for cleanup

Change-Id: Iab6436803c092bc769ab57703535f53208d38e4b