ISPN-4076 fix RHQ stats bytesRead and Write, remove for REST endpoint

REST endpoint does not provide bytesRead and bytesWritten statistics. We remove it from plugin. 
+ we fixed the right mapping of name for those 2 statistics to be understand properly by plugin.

Note: we possibly can remove them from the map completely but I prefer to let it there as we can better map what we are working with and what we are monitoring (for the future).