Tree Editor remove and add of nested objects

[ndoschek]

For the case, that properties can have nested arrays of objects, the tree has to determine if objects were added/removed and the correct commands has to be sent. This is the case for example for the RAM array of a Processor.

• Tree Editor: double check the retrieval of data differences (not only the feature field, also a valid method to retrieve added and removed objects from the array)
• JsonForms: double check why the array renderer is not accepting a detailed UI schema for the (as a workaround the unwanted columns were disabled via CSS)

[ndoschek]

To support investigation, here is a postman collection that includes a valid request to manipulate RAM elements.
Please update $ref of newly created RAM elements if you want to set their value or remove them again.
Coffee Editor.postman_collection.zip

[eneufeld]

I suggest to handle this after eclipse-emfcloud/emfcloud-modelserver#151 was merged, this would allow us to use a lib like https://github.com/Starcounter-Jack/JSON-Patch to create a patch and send it directly to the modelserver