Cardinality Validation View to Include Identifiers to Offenders

[chrisage]

Background:
In the RACK UI Cardinality Explorer Tab cardinality validations are listed in a tree hierarchy down to the entity type. To quicken debugging the cardinality issue we should expose the specific identifiers to the entities.

Acceptance Criteria:
Individual errors should be associated with specific identifiers to offending entities

Implementation Details:

Related: #986

[cuddihyge]

SemTK is not RACK specific. How do we propose that SPARQLgraph be told that "identifier" is the important property?
I'm not saying it can't be done (Franz Gruff) has a similar feature.
But it isn't an obvious or quick enhancement.
The RACK model doesn't even specify that "identifier" is special.
To mimic the functionality in Gruff, perhaps the user could set "identifier" as some kind of key property and SPARQLgraph could store the choice in a cookie and then use that information when executing and displaying the results of all CONSTRUCT queries. We'd need a mechanism to handle the cases where a CONSTRUCT query on the query tab does not include identifier. I don't care for Franz' solution of automatically modifying a query to add additional returns, so I don't think we should add identifier in those cases.