Mask and non-finite option refactor

[hpparvi]

This PR addresses Issue #252 by renaming the existing mask treatment options and introducing a new set. It also adds a documentation page with illustrations demonstrating each option's effect in practice, and it also adds a basic Black configuration to pyproject.toml and modifies flake8 in tox.ini to ignore E203, as described here. Finally, I started running black on the code I edited, which leads to somewhat larger diffs than from the actual functional changes alone.

The complete mask treatment option set now includes: apply, ignore, propagate, zero-fill, nan-fill, apply_mask_only, and appy_nan_only. Now is the best time to let everyone know if you are not happy with some of these choices, so please write if you have strong feelings against any :)

I chose propagate over the suggested mask_extraction_bin and apply_to_full_extraction_bin because it is more generic and can be used in any method or function requiring this behavior, rather than being limited to spectrum extraction. However, I'm happy to change this to something else if anyone can suggest a good, clear alternative.

Finally, should we go for apply_mask_only or apply-mask-only? The first option is probably grammatically better, but the other would be easier to remember.

[codecov]

Codecov Report

Attention: Patch coverage is 93.33333% with 11 lines in your changes missing coverage. Please review.

Project coverage is 86.16%. Comparing base (c31a9af) to head (e33f10e).

Files with missing lines	Patch %	Lines
specreduce/extract.py	91.52%	5 Missing ⚠️
specreduce/tracing.py	89.18%	4 Missing ⚠️
specreduce/core.py	95.45%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #254      +/-   ##
==========================================
+ Coverage   85.93%   86.16%   +0.22%     
==========================================
  Files          13       13              
  Lines        1166     1178      +12     
==========================================
+ Hits         1002     1015      +13     
+ Misses        164      163       -1     

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[hpparvi]

Looks like I still need to fix some minor issues with the docs. Here is a print of the doc page illustrating the mask treatment options.

mask_treatment.pdf

[hpparvi]

Also, I still need to improve the tests for the new code.

[tepickering]

Also, I still need to improve the tests for the new code.

shall i wait for you to do this before doing a review?

[hpparvi]

Also, I still need to improve the tests for the new code.

shall i wait for you to do this before doing a review?

Yes, please. I should have the last issues fixed today. I'll let you know when this is ready.

[hpparvi]

Okay, the PR is now ready for review, @tepickering .