Complete overwrite of RETROICOR computation to allow multiple physiological modalities and their interactions

[smoia]

Closes #

Turns out (or so I think) we were computing RETROICOR in a horrible (if not wrong) way due to a few oversights from reviewers (me included) and code authors.
In fixing the issues, I decided to just rewrite everything to improve computation and allow for interactive effects to be computed.

Proposed Changes

Phases:

• phases computation functions do not return physio objects nor accept them as as inputs to simplify interaction with main retroicor script.
• phases computation functions are now in a submodule of its own.
• phases are computed at the sampling rate of the physiological data, not of the neuroimaging data.
• phases computation is now vectorialised to make it more efficient. This changes it a little from the original formulae but it should be equivalent.
  Consequently, RETROICOR:
• retroicor computation function still accepts physio objects, both from physutils and from peakdet, or numpy arrays, and still returns accordingly, but it does not use the usual decorator for that (instead it handles it internally).
• retroicor computation function now accept both cardiac and respiratory data at the same time, thus allowing for interaction regressors to be computed as well.
• if at least one physutils.Physio object was given as input, the function returns the physutils.Physio object that were provided with the computed metics in the metrics metadata. If the other entry was an array, it will still return a new object based on that array.
• otherwise, is a peakdet.Physio or an array-like data was given as input, the function returns the metric itself.
• the metric is always a dictionary with two dictionaries inside, one for retroicor, one for the phases; these are two dictionaries themselves, with one entry per slice time.

Tagging @CesarCaballeroGaudes @afni-dglen @mrikasper because of your expertise with RETROICOR and its implementation in code. Tagging @m-miedema and @me-pic for your expertise on phys2denoise.

Change Type

• bugfix (+0.0.1)
• minor (+0.1.0)
• major (+1.0.0)
• refactoring (no version update)
• test (no version update)
• infrastructure (no version update)
• documentation (no version update)
• other

Checklist before review

• I added everything I wanted to add to this PR.
• [Code or tests only] I wrote/updated the necessary docstrings.
• [Code or tests only] I ran and passed tests locally.
• [Documentation only] I built the docs locally.
• My contribution is harmonious with the rest of the code: I'm not introducing repetitions.
• My code respects the adopted style, especially linting conventions.
• The title of this PR is explanatory on its own, enough to be understood as part of a changelog.
• I added or indicated the right labels.

• I added information regarding the timeline of completion for this PR.

• Please, comment on my PR while it's a draft and give me feedback on the development!

[smoia]

Also @alaurasparsi this is of interest for you!

[codecov]

Codecov Report

❌ Patch coverage is 8.08081% with 91 lines in your changes missing coverage. Please review.
✅ Project coverage is 44.55%. Comparing base (34be772) to head (4fad72f).
⚠️ Report is 17 commits behind head on master.

Files with missing lines	Patch %	Lines
phys2denoise/metrics/multimodal.py	4.47%	64 Missing ⚠️
phys2denoise/metrics/phase.py	15.62%	27 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #70      +/-   ##
==========================================
- Coverage   53.85%   44.55%   -9.31%     
==========================================
  Files           8        9       +1     
  Lines         596      606      +10     
==========================================
- Hits          321      270      -51     
- Misses        275      336      +61     

Files with missing lines	Coverage Δ
phys2denoise/metrics/cardiac.py	35.00% <ø> (-19.35%)	⬇️
phys2denoise/metrics/chest_belt.py	92.59% <ø> (+0.21%)	⬆️
phys2denoise/metrics/phase.py	15.62% <15.62%> (ø)
phys2denoise/metrics/multimodal.py	12.00% <4.47%> (-14.83%)	⬇️

... and 1 file with indirect coverage changes

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[smoia]

Makes more sense to invert order to follow input order