Add notebook for RF QSO targets selection

[echaussidon]

Hi,

I write a jupyter notebook explain how the RF for qso targets selection were generated.

I also put the scripts for the training in : desitarget/train

Files are saved in Nersc at : /global/cfs/cdirs/desi/target/analysis/RF

[echaussidon]

For the review : @geordie666

[geordie666]

@echaussidon: Thanks for your extensive effort! I didn't have time to try the full tutorial, but the initial parts that I did try worked well.

Documentation tests are failing because the api.rst file that tracks documentation for Read The Docs needs to be update to reflect your new py/desitarget/train/ directory structure.

In addition to making the changes I've highlighted in the review, you'll also need to update the api.rst file in your branch to add the modules in each of your __init.py__ files.

Also, in the api.rst file, make sure to remove the reference to .. automodule:: desitarget.train.train_mva_decals which you are removing as a directory in py/desitarget/train/.

Once the documentation (sphinx) tests pass, I'm happy to merge this.

[echaussidon]

@geordie666 : I think every thing works now ! I'm not very familiar with api.rst, ect ...

Thanks for your review.

[geordie666]

Thanks @echaussidon. And, thanks also for fixing-up all of the code style. I usually address that in my "spare time", but it's definitely good practice to adhere to PEP 8 style. I'll merge this soon.