Get Citrix MCS RAM/Disk Cache Usage Script Not working on newer VDAs

[scriptbased]

Originally reported by Rob Sheppard on the World of EUC community slack:

Script https://github.com/controlup/script-library/tree/master/Get%20Citrix%20MCS%20RAM%20%20Disk%20Cache%20Usage as also discussed in this blog https://www.controlup.com/everything-you-need-to-know-about-the-new-citrix-mcs-io-acceleration/ seems to have issues with more recent VDA versions, likely due to Citrix changing the name of the performance counters:

This script probably needs to be updated to use the updated perf counter names and possibly some logic that determines which set to use based on VDA version check.

Since this is an older script, it also doesn't use ControlUp's scripting standards.

cc @Rorymon