Changes to Curated SNB cube catalog

added the non-success response with the status 500

added the optional property meta/stale_since to the response with the 200 status

added the optional property meta/data_age_days to the response with the 200 status

added the optional property meta/notes to the response with the 200 status

added the optional property meta/period to the response with the 200 status

the response property data/items/category became optional for the status 200

the response property data/items/cube_id became optional for the status 200

the response property data/items/endpoint became optional for the status 200

the response property data/items/frequency became optional for the status 200

the response property data/items/name became optional for the status 200

response property data/items/category list-of-types was widened by adding types null to media type application/json of response 200

response property data/items/cube_id list-of-types was widened by adding types null to media type application/json of response 200

response property data/items/endpoint list-of-types was widened by adding types null to media type application/json of response 200

response property data/items/frequency list-of-types was widened by adding types null to media type application/json of response 200

response property data/items/name list-of-types was widened by adding types null to media type application/json of response 200

added the optional property code to the response with the 401 status

added the optional property code to the response with the 429 status

added the optional property code to the response with the 503 status

added the optional property hint to the response with the 401 status

added the optional property hint to the response with the 429 status

added the optional property hint to the response with the 503 status

added the optional property plan to the response with the 401 status

added the optional property plan to the response with the 429 status

added the optional property plan to the response with the 503 status

added the optional property reason to the response with the 401 status

added the optional property reason to the response with the 429 status

added the optional property reason to the response with the 503 status