Compare DCMIP Kessler microphysics and CloudMicrophysics 1M scheme for the supercell test case

It'd be interesting to see how differences in the microphysics scheme lead to differences in the supercell simulations. Hopefully we can make this cheap enough to put the comparison into the docs, but its ok if not. Eventually we should create a `sandbox` directory for research scripts that we can't run in CI but are still useful to reference.