added"@type": "@id" for image and removed imageUrl

[yibeichan]

had discussion with @satra and @djarecka on slack about image and imageUrl, we decide

• adding "@type": "@id" here

  reproschema/contexts/generic

  Lines 17 to 20 in 5453e3c

  	"image": {
  	"@id": "schema:image",
  	"@type": "@id"
  	},

  , otherwise image can't pass the validation
• removing imageUrl since imageUrl and image are the same now and only image was used in demo-protocol and reproschema-library

we can integrate these changes for the next release

[yibeichan]

@satra , i saw your comment on the cookicutter issue, but is related to this PR too
since imageUrl was created for a reason, we need to figure out why things work/don't work.
i provided the background info and problem identified here, you can read problem identified first,

background info

1. in schema.org, schema:image is defined as the following; it can be either an URL or an ImageObject

   image
   A Schema.org Property
   Thing > Property :: image
   [more...]

   Canonical URL: https://schema.org/image
   Check for open issues.

An image of the item. This can be a URL or a fully described ImageObject.
Values expected to be one of these types

[ImageObject](https://schema.org/ImageObject)
[URL](https://schema.org/URL)

Used on these types

[Thing](https://schema.org/Thing)

2. in schema.org shacl, image defined as

[ sh:or ( [ sh:node :ValidSchemaImageObject ] [ sh:node :ValidSchemaURL ] ) ;
            sh:path schema1:image ],

3. in reproschema generic, we have

   reproschema/contexts/generic

   Lines 17 to 23 in e0d83d0

   	"image": {
   	"@id": "schema:image"
   	},
   	"imageUrl": {
   	"@id": "schema:image",
   	"@type": "@id"
   	},

   
   imageUrl is defined as @id an identifier in schema.org, so
   Values expected to be one of these types

• PropertyValue
• Text
• URL

4. in reproschema shacl, we have

[ sh:or ( [ sh:nodeKind sh:IRI ] [ sh:node reproschema:MediaObjectShape ] ) ;
            sh:path schema:image ]

it means that we expect image to be either IRI or reproschema:MediaObjectShape

here is the definition of reproschema:MediaObjectShape

reproschema/releases/1.0.0-rc4/reproschema-shacl.ttl

Lines 354 to 362 in e0d83d0

	reproschema:MediaObjectShape a sh:NodeShape ;
	sh:closed true ;
	sh:ignoredProperties ( rdf:type ) ;
	sh:property [ sh:minCount 1 ;
	sh:nodeKind sh:IRI ;
	sh:path schema:contentUrl ],
	[ sh:datatype rdf:langString ;
	sh:maxCount 1 ;
	sh:path schema:inLanguage ] .

problem identified

"image": "https://picsum.photos/500/400" failed but "imageUrl": "https://picsum.photos/500/400" succeed
why? because https://picsum.photos/500/400 is interpreted as Literal not an IRI, see the error here

ValueError: Validation Report
Conforms: False
Results (1):
Constraint Violation in OrConstraintComponent (http://www.w3.org/ns/shacl#OrConstraintComponent):
	Severity: sh:Violation
	Source Shape: [ sh:or ( [ sh:nodeKind sh:IRI ] [ sh:node reproschema:MediaObjectShape ] ) ; sh:path schema:image ]
	Focus Node: <http://localhost:8000/activities/voiceActivity/items/audio_image_record_item>
	Value Node: Literal("https://picsum.photos/500/400", lang=en)
	Result Path: schema:image
	Message: Node Literal("https://picsum.photos/500/400", lang=en) does not conform to one or more shapes in [ sh:nodeKind sh:IRI ] , [ sh:node reproschema:MediaObjectShape ]

while imageUrl as @id can support text. I tested it as "imageUrl": "some random text for testing" still passed the validation.

so, now we know what the problem is: our URL can't be interpreted as IRI properly, rather, it's treated as literal.

[yibeichan]

@djarecka hi, based on our recent updates, what should we do with this PR? merge it or ditch it?

[djarecka]

i thing we can close it, and I will remove imageUrl from the new context