Adding a dumpload of documentation

[valeriupredoi]

sister PR to ESMValGroup/ESMValTool#1172

Documentation split (#89) should be completed before this can be merged.

[valeriupredoi]

@mattiarighi @bouweandela @ledm as a word of plz plz do this: in documentation function and parameter and units and error names use verbatim and use Iris (capitalized) since they use Iris on their readthedocs. Cheers! That will make things much easier 🍺

[valeriupredoi]

also here's how I'll do stuffs: I am writing furiously like a proper reporter from Rolling Stone and I will post here when I'm done with different modules (eg tomorrow I'll be done with preprocessor.inc and I'll post I'm done). In the meantime pls pls no change requests or suggestions for the WIP module. When I'm done with each module then I'll shout it and leave it and it's all yours for changing it 🍺

[mattiarighi]

Can you put this in draft mode?
So you can let us know when it's ready for review.

[valeriupredoi]

Can you put this in draft mode?
So you can let us know when it's ready for review.

@mattiarighi I believe it is easier for you guys to review each module when I call it done (on my side) than reviewing the whole shebang because that's gonna be a lot to go through if not doing it module by module 🍺

[valeriupredoi]

OK preprocessor.inc is done from my side: @jvegasbsc could you pls input the stuff under CMORization and dataset-specific fixes 🍺 Also, the others, lease feel free to edit preprocessor.inc, I'll always pull regularily so there's no conflicts (pls don't prompt me to change things since I'm moving on to _data_finder now) 📚

[valeriupredoi]

OK datafinder.inc is done from my side

[BenMGeo]

I like the text you propose here. It's easy to find in the masking section.

You might comment out the time_window as it falls back to default then?
Maybe even the min_value, if you set the default to -inf.

[mattiarighi]

Thanks for reviewing. Your suggestions have been implemented.