Bring in new CMIP7 compsets, user-mods and testing to easily give the CMIP7 output for experiments

We have copies of CMIP6 compsets, user-mods and testing for this right now. We need to make a new copy for CMIP7 so we can start to customize it for the new CMIP7 experiments. We can leave the CMIP6 version around for awhile, but should remove it when the CMIP7 is reasonably solid.

CESM wide we also need to discuss this and make sure each component will be handling this the same way. We'll want the fully coupled compsets to run CMIP7 experiements to be setup to get the right set of initial conditions, as well all the required history output for each component that's required.

@briandobbins