New datasets for demonstrating / validating the Inheritance principle

[Lestropie]

Related to bids-standard/bids-specification#2155.

In looking at the specification content on the Inheritance Principle, across many versions (retrospective and speculative), it has become clear that showing exemplar filesystem structures / JSON metadata contents has been totally unfit for purpose.
Moreover, even worse, there were many circumstances that were explained in text as hypothetical modifications to the presented filesystem structures, which just opens to floodgates for confusion.

I have therefore gone to the effort of explicitly instantiating each of these examples as exemplar datasets; both what weas shown in the specification and all hypothetical manipulations thereof.
Other datasets I have specifically crafted in order to highlight what the differences in validation should be depending on which particular IP ruleset is instantiated.

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One crucial detail here is that many of these examples are defined as they are specifically because they should fail validation. Am I correct in inferring that all datasets in the bids-examples repository should pass validation (with the potential exclusion of content not yet included in a tagged specification), and anything that fails validation should instead be going into bids-validator/tests/data?

I am also aware that the addition of these data will result in failure of run_tests.sh.

Maintainers will need to advise on whether some of these datasets need to be moved, whether some of these datasets should be excluded from validator testing, or whether merging the PR needs to be deferred until requisite rectifications to the validator are made.