Drupal REST syntax has changed, claw-jsonld could be altered

[whikloj]

In working on #527 I have done a lot of PATCHing and it appears that this syntax (https://www.drupal.org/docs/8/core/modules/rest/4-patch-for-updating-content-entities) is not correct and this syntax (https://www.drupal.org/docs/8/core/modules/rest/javascript-and-drupal-8-restful-web-services) is.

I was looking at the nodes stuff, because it was the stuff that worked for FedoraResources out of the box.

Now working to denormalize Json-LD the denormalize function is looking for '_links' at the root level.
https://github.com/Islandora-CLAW/claw-jsonld/blob/8.x-1.x/src/Normalizer/ContentEntityNormalizer.php#L162

ie.

{
  @graph : {....},
  "_links" : { "type" : { "href" : "http://localhost:8000/rest/type/fedora_resource/rdf_source"}}
}

This could be changed to

{
  @graph : {...},
  "type":[{"target_id":"rdf_source"}]
}

I think they did this because you POST to an endpoint with the entity in it and otherwise you PATCH to the actual entity URL.

[whikloj]

Actually we are going to use a header to pass this information, so the function will need to be altered, but not yet.

[whikloj]

I'll do this as part of #527