Structured data 2 (#645)

* Structured data refactor - multi-index tables, remove need for manual mods to the Cassandra tables

* Tech spec updated to track implementation

specs/api/components/schemas/query/ObjectsQueryRequest.yaml

@@ -1,40 +0,0 @@
-type: object
-description: |
-  Objects query request - GraphQL query over knowledge graph.
-required:
-  - query
-properties:
-  query:
-    type: string
-    description: GraphQL query string
-    example: |
-      query GetPerson($id: ID!) {
-        person(id: $id) {
-          name
-          email
-          knows {
-            name
-          }
-        }
-      }
-  variables:
-    type: object
-    description: GraphQL query variables
-    additionalProperties:
-      type: string
-    example:
-      id: "https://example.com/person/alice"
-  operation-name:
-    type: string
-    description: Operation name (for multi-operation documents)
-    example: GetPerson
-  user:
-    type: string
-    description: User identifier
-    default: trustgraph
-    example: alice
-  collection:
-    type: string
-    description: Collection to query
-    default: default
-    example: research