new mistral collections

intake/cmip6_collection_mistral.yml

intake/collection_input_mpim_ge.yml

intake/mistral-cmip5-collection.yml

intake/mistral-cmip6-collection.yml

intake/mistral-mpige-collection.yml

intake/mpige_cmorized_mistral.yml

intake/obs.yml

notebooks/intake/intake_CMIP.ipynb

pymistral.yml