[ENH] drop "CPP style" group support

[Remi-Gau]

fixes #299
fixes #256
fixes #290
fixes #275

This affects a LOT of things!!!! Sorry.

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Main changes

• modify the way groups are handled

opt.subjects is now updated if user asks for some opt.groups, the groups variable is removed.

• simplify workflows and batch to remove any loop over groups
• update tests

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Other changes

• refactor test and improve test code base
• rename variable subID by subLabel

[Remi-Gau]

Will most likely merge this one before all the other things we have pending as this is likely going to create a lot of merge conflicts.

[codecov]

Codecov Report

Merging #314 (a92a480) into dev (c3a76e0) will increase coverage by 0.87%.
The diff coverage is 33.21%.

@@            Coverage Diff             @@
##              dev     #314      +/-   ##
==========================================
+ Coverage   63.91%   64.78%   +0.87%     
==========================================
  Files         104      104              
  Lines        1649     1616      -33     
==========================================
- Hits         1054     1047       -7     
+ Misses        595      569      -26     

Impacted Files	Coverage Δ
src/QA/anatomicalQA.m	0.00% <0.00%> (ø)
src/QA/functionalQA.m	0.00% <0.00%> (ø)
src/batches/setBatchCoregistrationFmap.m	0.00% <0.00%> (ø)
src/getFuncVoxelDims.m	100.00% <ø> (ø)
src/getInfo.m	94.73% <ø> (ø)
src/getPrefix.m	100.00% <ø> (ø)
src/reports/copyFigures.m	0.00% <0.00%> (ø)
src/utils/printProcessingSubject.m	100.00% <ø> (ø)
src/workflows/bidsConcatBetaTmaps.m	0.00% <0.00%> (ø)
src/workflows/bidsCreateVDM.m	0.00% <0.00%> (ø)
... and 30 more

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