upgrade calibration and CMIP example to use ewatercycle-da for ensemble

Both the calibration example and the CMIP example would be better if they used the (new) ewatercycle-da plugin that supports ensembles as a native construct. Changing those examples would demonstrate the power of ewatercycle-da and serve as a first example of a parallel use case.

It would also be a good test case for eWaterCycle-da and could potentially lead to issues and improvements in that repo.