Changes to Query relationships

api operation id getRelationTuples removed and replaced with getRelationships

api tag relationship added

api tag read removed

removed the non-success response with the status 500

the query request parameter namespace became optional

the query request parameter object became optional

the query request parameter relation became optional

the query request parameter namespace became required

the query request parameter object became required

the query request parameter relation became required

api operation id getRelationships removed and replaced with getRelationTuples

api tag read added

api tag relationship removed

added the non-success response with the status 500