Add reviewer-tree items to an existing submission

Copies items from the project's reviewer tree into the submission. `itemPaths` are relative to `project/{projectId}/reviewer` and `destinationPath` is relative to `submission/{submissionId}` (omit it to add at the submission root; a destination folder that does not exist returns 404). Marks the copied assets as belonging to the submission and recomputes its inventory. Requires `canAddSubmittionItems`; the submission must belong to `projectId`.

curl -X POST "https://example.com/projects/497f6eca-6276-4993-bfeb-53cbbbba6f08/submission/497f6eca-6276-4993-bfeb-53cbbbba6f08/add" \  -H "Content-Type: application/json" \  -d '{    "itemPaths": [      "Renders/final.png",      "Renders/alt"    ]  }'

{  "count": 1,  "virtualDestination": true,  "published": true,  "errors": [    {      "type": "string",      "message": "string",      "data": null    }  ]}