dandiset.yaml: add "standards" section?

[yarikoptic]

I envision it to be primarily an auto-populated (e.g. using dandi organize) list of records with fields

• name: name of the standard (nwb, bids, dandiset, dandi-layout if we do not enforce, ...)
• versions: string or a list of strings - versions of the corresponding standard found in the dandiset (e.g., .nwb files could be a cocktail of NWB versions)
• extensions: a list of detected extensions to the standard (e.g., could be NWB extensions, nifti extensions, etc) probably again as a list of records with version field.
• options: this one is debatable one. I thought to (ab)use it to e.g. describe dandi-layout options (minimization of keys, or entire filename pattern, etc).

It might be that it would even relate to the "scope" aspect (#1) but likely it is too inherent within dandiset.yaml itself, and should eventually be described there.

Purpose: provide overview in the used standards. Could simplify search for datasets of particular qualities (bids, or the ones consistently layed out with dandi organize) .

[yarikoptic]

I think "standards" are already reflected in our dandi-schema. NWB extensions aren't and I don't think options should be part of dandiset.yaml although might. I will transfer this to dandi-schema since discussing those might still have value.