EXOS port statistics summary available

[Dave_Hammers]

By customer request, created an EXOS port statistics summary display that consolidates these separate EXOS commands into one display:

• show ports statistics
• show ports rxerrors
• show ports txerrors
• show ports congestion
• show ports qosmonitor congestion

https://github.com/extremenetworks/ExtremeScripting/tree/master/EXOS/Python/portsum