provide LD-ready `ls -f jsonld{,_pp}` output?

@satra , sorry for a basic LD question -- how would we do that? ;)

@surchs is interested to see how dandischema records might look like in json-ld and might be interested to use/help with all json-ld'ification.

ATM we have a https://raw.githubusercontent.com/dandi/schema/master/releases/0.4.4/context.json which we do provide in json representation of the metadata for Dandiset:

an example of a "json_dict" dump of a Dandiset

```shell
(dandisets) dandi@drogon:/mnt/backup/dandi/dandisets$ for ds in 000*; do python -c "from dandischema.models import Dandiset; import yaml; ds = Dandiset.unvalidated(**yaml.load(open('$ds/dandiset.yaml'), Loader=yaml.FullLoader));print(ds.json(indent=2))" && echo $ds; break; done
{
"@context": "https://raw.githubusercontent.com/dandi/schema/master/releases/0.4.4/context.json",
"about": [
{
"identifier": "UBERON:0002436",
"name": "primary visual cortex",
"schemaKey": "Anatomy"
}
],
"access": [
{
"contactPoint": {
"email": "petersen.peter@gmail.com",
"schemaKey": "ContactPoint"
},
"status": "dandi:OpenAccess"
}
],
"assetsSummary": {
"approach": [
{
"name": "electrophysiological approach",
"schemaKey": "ApproachType"
},
{
"name": "behavioral approach",
"schemaKey": "ApproachType"
}
],
"dataStandard": [
{
"identifier": "RRID:SCR_015242",
"name": "Neurodata Without Borders (NWB)",
"schemaKey": "StandardsType"
}
],
"measurementTechnique": [
{
"name": "signal filtering technique",
"schemaKey": "MeasurementTechniqueType"
},
{
"name": "fourier analysis technique",
"schemaKey": "MeasurementTechniqueType"
},
{
"name": "spike sorting technique",
"schemaKey": "MeasurementTechniqueType"
},
{
"name": "behavioral technique",
"schemaKey": "MeasurementTechniqueType"
},
{
"name": "multi electrode extracellular electrophysiology recording technique",
"schemaKey": "MeasurementTechniqueType"
}
],
"numberOfBytes": 2559248010229,
"numberOfFiles": 101,
"numberOfSubjects": 16,
"schemaKey": "AssetsSummary",
"species": [
{
"identifier": "http://purl.obolibrary.org/obo/NCBITaxon_10090",
"name": "House mouse",
"schemaKey": "SpeciesType"
}
],
"variableMeasured": [
"DecompositionSeries",
"LFP",
"Units",
"Position",
"ElectricalSeries"
]
},
"citation": "Senzai, Yuta; Fernandez-Ruiz, Antonio; Buzs\u00e1ki, Gy\u00f6rgy (2021) Layer-Specific Physiological Features and Interlaminar Interactions in the Primary Visual Cortex of the Mouse (Version draft) [Data set]. DANDI archive. https://dandiarchive.org/dandiset/000003/draft",
"contributor": [
{
"affiliation": [],
"includeInCitation": true,
"name": "Senzai, Yuta",
"roleName": [
"dcite:Author",
"dcite:ContactPerson",
"dcite:DataCollector",
"dcite:FormalAnalysis"
],
"schemaKey": "Person"
},
{
"affiliation": [],
"identifier": "0000-0001-8481-0796",
"includeInCitation": true,
"name": "Fernandez-Ruiz, Antonio",
"roleName": [
"dcite:Author",
"dcite:FormalAnalysis"
],
"schemaKey": "Person"
},
{
"affiliation": [
{
"contactPoint": [],
"identifier": "https://ror.org/005dvqh91",
"includeInCitation": false,
"name": "New York University Langone Medical Center",
"roleName": [],
"schemaKey": "Affiliation",
"url": "http://nyulangone.org/"
}
],
"identifier": "0000-0002-3100-4800",
"includeInCitation": true,
"name": "Buzs\u00e1ki, Gy\u00f6rgy",
"roleName": [
"dcite:Author"
],
"schemaKey": "Person"
}
],
"description": "Data from \"Layer-Specific Physiological Features and Interlaminar Interactions in the Primary Visual Cortex of the Mouse\" Senzai, Fernandez-Ruiz, Buzsaki, Neuron 2019. Electrophysiology recordings of hippocampus during theta maze exploration.",
"ethicsApproval": [],
"id": "DANDI:000003/draft",
"identifier": "DANDI:000003",
"keywords": [
"cell types",
"cortical layers",
"current source density",
"laminar recordings",
"optogenetics",
"oscillations",
"primary visual cortex",
"sleep",
"alpha rhythm"
],
"license": [
"spdx:CC-BY-4.0"
],
"manifestLocation": [],
"name": "Layer-Specific Physiological Features and Interlaminar Interactions in the Primary Visual Cortex of the Mouse",
"protocol": [],
"relatedResource": [
{
"identifier": "doi:10.1016/j.neuron.2016.12.011",
"relation": "dcite:IsDescribedBy",
"url": "https://doi.org/10.1016/j.neuron.2016.12.011"
}
],
"repository": "https://dandiarchive.org/",
"schemaKey": "Dandiset",
"schemaVersion": "0.4.4",
"studyTarget": [],
"url": "https://dandiarchive.org/dandiset/000003/draft",
"version": "draft",
"wasGeneratedBy": [],
"acknowledgement": null,
"dateCreated": null,
"dateModified": null
}

```

but I guess many items/contexts are just "ending" at `dandi:` and even `age` is not really "linked" anywhere.

and if we do add @context to `Dandiset`'s json_dict dump, it seems absent from an asset record

```shell
$> python -c 'import json; from dandischema.models import Asset; from dandi.dandiapi import DandiAPIClient as C; c=C(); ds = c.get_dandiset("000004"); asset = next(ds.get_assets());print(json.dumps(Asset(**asset.get_raw_metadata()).json_dict(), indent=2))'
{
"id": "dandiasset:38304fe9-5f37-4c0d-a741-9cf2bafab9ff",
"schemaKey": "Asset",
"schemaVersion": "0.4.4",
"keywords": [
"Intracranial Recordings",
"Intractable Epilepsy",
"Single-Unit Recordings",
"Cognitive Neuroscience",
"Learning",
"Memory",
"Neurosurgery"
],
"access": [
{
"schemaKey": "AccessRequirements",
"status": "dandi:OpenAccess"
}
],
"repository": "https://dandiarchive.org/",
"wasGeneratedBy": [
{
"id": "urn:uuid:4fa83952-03c6-4868-b9dd-1247ac8ae6b4",
"schemaKey": "Activity",
"name": "Metadata generation",
"description": "Metadata generated by DANDI cli",
"wasAssociatedWith": [
{
"schemaKey": "Software",
"identifier": "RRID:SCR_019009",
"name": "DANDI Command Line Interface",
"version": "0.22.0",
"url": "https://github.com/dandi/dandi-cli"
}
]
}
],
"contentSize": 73156888,
"encodingFormat": "application/x-nwb",
"digest": {
"dandi:sha2-256": "c4994d36fe0c7f0c19917b452c9355567ade7f449f17156dffea5cd5e53e519f",
"dandi:dandi-etag": "72aede0fb38eef9a1e94350c6fe7382b-2"
},
"path": "sub-P10HMH/sub-P10HMH_ses-20060901_ecephys+image.nwb",
"dateModified": "2021-07-01T16:30:11.012406-04:00",
"blobDateModified": "2020-10-20T23:40:40.971199-04:00",
"approach": [
{
"schemaKey": "ApproachType",
"name": "electrophysiological approach"
}
],
"measurementTechnique": [
{
"schemaKey": "MeasurementTechniqueType",
"name": "spike sorting technique"
}
],
"variableMeasured": [
{
"schemaKey": "PropertyValue",
"value": "Units"
}
],
"wasAttributedTo": [
{
"schemaKey": "Participant",
"identifier": "P10HMH",
"sex": {
"schemaKey": "SexType",
"identifier": "http://purl.obolibrary.org/obo/PATO_0000384",
"name": "Male"
},
"species": {
"schemaKey": "SpeciesType",
"identifier": "http://purl.obolibrary.org/obo/NCBITaxon_9606",
"name": "Human"
}
}
],
"identifier": "38304fe9-5f37-4c0d-a741-9cf2bafab9ff",
"contentUrl": [
"https://api.dandiarchive.org/api/assets/38304fe9-5f37-4c0d-a741-9cf2bafab9ff/download/",
"https://dandiarchive.s3.amazonaws.com/blobs/284/eb3/284eb346-0bc5-42a6-9b33-268e6b0b0bde"
]

```