restore model rainfall max and amount fields to the output dataset

[stevehadd]

in the refactoring of PR #39 , some of the model data fields that were being extracted were accidentally deleted when the decision was made to longer include model accumulations in the final dataset. These fields should be put back into the event configs:

• rainfall_rate_max
• convective_rainfall_rate_max
• lwe_snowfall_rate_max
• lwe_convective_snowfall_rate_max
• thickness_of_rainfall_amount
• thickness_of_convective_rainfall_amount
• lwe_thickness_of_snowfall_amount
• lwe_thickness_of_convective_snowfall_amount

[stevehadd]

actually i think I got confused. These variable are actually relating to 3 hour accumulations, even though the variable name in the cube metadata doesn't mention this. I just confused myself, these are taken out deliberately, so I will close this issue. @hannahbrown7 I assume you will be updating the EDA notebooks at some point so that plots from accumulations are removed, or maybe just optional ?