Add REQUIRED_MODEL_VERSION option so that build/run will abort if it's set and MODEL_VERSION doesn't equal it

I'd like to add this as an optional feature. The idea is to add a new field REQUIRED_MODEL_VERSION that would by default be set to None. If set to None, nothing different happens. However, if the user does set it to anything else, at the build/and or run phase REQUIRED_MODEL_VERSION will be compared to MODEL_VERSION, and if the strings are different the phase would abort.

Since, provenance is done slightly different between cesm and e3sm it might have to be a feature that was only added to cesm. But, if e3sm wanted it as well, that might be an option too to get it to work for both. I'm just not completely sure about that. So if it's desired for e3sm, I need e3sm folks to chime in.

I want to start this as a discussion. CTSM folks think this would be useful to the scientific workflow. I did talk to @billsacks about it a bit. If people think this is a bad idea, I especially need people to chime in. Otherwise, I'll plan on working on this myself. I don't think this will be hard to do....