Infrastructure to bring isotopes as tracers into CISM

[Katetc]

One of the basic "to dos" for the isotope enabled CESM will be adding the code to take isotopes from the Wrapper and fill in tracer arrays with the isotopic values from the coupler. Basically, code to pack the tracer arrays with info from the coupler. This is directly related to the issue in CISM-Wrapper as well, so likely some coordination needed between tags here.