[SCHEMA] Add derivatives entities to the schema

[tsalo]

This stems from mne-tools/mne-bids#449 (comment).

Changes proposed:

• Add the derivatives entities (res, den, label, and desc) to the schema.
• Redefine the space entity so it works for EEG/MEG/iEEG and MRI data.
• Generate the updated Entities page.

[effigies]

Looks reasonable. I've added a little bit of extra content so they don't look quite so bare.

[adam2392]

Is it possible to enumerate which ones are referred to as source_entities and then which entities are reserved for derivatives? So I would imagine a list of supported raw/source entities and then a running list of derivative entities?

E.g. desc from what I understand is only meant for derivatives, so it should never be present in a BIDS source dataset

[tsalo]

@adam2392 We could add a field to the schema that describes scope, but I think that could quickly become confusing (e.g., space is raw for MEG/EEG/iEEG but derivatives-only for MRI). Would it be enough if I expanded the descriptions to clarify that they can only be used with Derivatives data?

[adam2392]

@adam2392 We could add a field to the schema that describes scope, but I think that could quickly become confusing (e.g., space is raw for MEG/EEG/iEEG but derivatives-only for MRI). Would it be enough if I expanded the descriptions to clarify that they can only be used with Derivatives data?

Oh okay yeah that sounds good! I suppose that's a pretty simple fix for now and makes sense given what you said. Is desc the only Derivatives-only entity?

[sappelhoff]

@tsalo @effigies unless you have final issues with this, I think one of you can merge this.