Mediator XPU ID Hardcoded to 1

[ctrostel90]

The mediator Cyclic and other methods use a hardcoded XpuTcIo(1) which prevents the FB_Xts being used on a System with more than one XPU.

Ideally, to simply things a property could be made for the Mediator that is initalized to 1. This would allow for most users (who only have a singular XPU) to not have to deal with the setting but still allow users to use the Base with > 1 XPU

[netbymatt]

A property would need to be initialized in code and might be initialized too late unintentionally for some of the environment-related calls that happen in mediator.cyclic. Maybe this is better as a generic constant like the number of movers.