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/websocket/components/messages/requests/ObjectsRequest.yaml

@@ -1,26 +0,0 @@
-type: object
-description: WebSocket request for objects service (flow-hosted service)
-required:
-  - id
-  - service
-  - flow
-  - request
-properties:
-  id:
-    type: string
-    description: Unique request identifier
-  service:
-    type: string
-    const: objects
-    description: Service identifier for objects service
-  flow:
-    type: string
-    description: Flow ID
-  request:
-    $ref: '../../../../api/components/schemas/query/ObjectsQueryRequest.yaml'
-examples:
-  - id: req-1
-    service: objects
-    flow: my-flow
-    request:
-      query: "{ entity(id: \"https://example.com/entity1\") { properties { key value } } }"