[INFRA] use macro to render examples in a "tree" like fashion

[Remi-Gau]

fixes #807

This is a first attempt to see what it could look like to render examples differently from templates

Current issues:

• handling directories that mix files and directories
• extra return carriage make some examples to "spacious" vertically
• apply to:
  • MEG
  • EEG
  • iEEG
  • PET
  • beh, physio, task...
  • derivatives
  • appendices
• add doc
  • to code
  • to CONTRIBUTING
• create a separate module for example code
• move jupyter notebook
• remove original examples

---

Writing complex examples can get a bit annoying: almost tempted to have examples "encoded" in separate yaml files. Might be an overkill as most examples will remain fairly simple

[Remi-Gau]

I have updated all the examples that seemed relevant.

I have left the old version below for an easier before / after comparison on the rendering:
https://bids-specification--837.org.readthedocs.build/en/837/

Let me know what you think.

Once I get the green light on this on the "content", I will do some clean up and add some doc.

[sappelhoff]

Have you tried ditching the relative imports?

That is, don't do from . import X but from <explicit-package-name> import X.

Apart from the fact that it might solve the issue here, explicit (absolute) imports are often more readable and transparent: https://stackoverflow.com/a/4209771/5201771

It'll have to be fixed in several places, also consider the fix I posted on mattermost for your tools/examplecode/__init__.py file :-)

[Remi-Gau]

OK all of CI is green on this one.

the PDF looks fine to me.

let me know if I am missing something in terms of doc or something.

[sappelhoff]

nice! just some minor comments, this is great :)

[tsalo]

Everything looks great to me. I think you just need to deal with the merge conflicts, but other than that I think it's good to go.

[Remi-Gau]

Everything looks great to me. I think you just need to deal with the merge conflicts, but other than that I think it's good to go.

Thanks for the reminder @tsalo : I had totally forgotten to cross check this one.

[sappelhoff]

Thanks a lot @Remi-Gau this is great!