feature: addAttachment

```js
await profiles.addAttachment(model_id, attachmentName, stream/file)
```

If the attachments flag is true, then use the `storage` service to add an unstructured object/file, then within the model, add the document name to a `$attachments` property, that lists all attachments added to this model document.

### Modes

- atomic: if the update to the data service fails, then rollback the upload of the file by deleting it
- non-atomic: if the update to the data service fails, then return the fact that the update operation failied even though the upload file was successful.