add wet day frequency correction about dodola

[brews]

@dgergel Hmmm. Thinking about making the interface natural... I feel like you're describing it as an option to bias-correction. How about start by setting it as a boolean flag to biascorrect:

dodola biascorrect {insert usual options here} --wetday-correction

This feels pretty natural to me.

It would be an option to the bias correction service, but you can implement it in the core however you'd need, of course.

[dgergel]

It needs to be more than an option to bias correction because it will also come into the pipeline after downscaling (the post-processing step is after both bias correction and downscaling). So, I'm fine with the above syntax, but we will also need something along the lines of:

dodola wetday_correction <input zarr store> <output zarr store> --post-process 

So, seems like we could have pre-process and post-process flags to the wetday_correction service, and add it as a boolean flag to the bias correction service? @brews how does that sound?

[brews]

@dgergel @dgergel Hmm. So then the post-processing step is identical for downscaling?

What if we add a similar flag to dodola downscale, rather than making it an explicit, new step:

dodola downscale <blah blah blah> --wetday-correction

The wet-correction in downscaling and bias correction might share the same functions/classes in dodola/core.py (which we can unit test)?

Does this solve your issue or it might be that there is something critical that I'm totally missing?