feat(assets): remove assetId in upsert

[Leagian]

What does this PR do ?

This PR is an update of the previous one, the assetId has been removed to prevent displaying the _id in the API action. With this update, you can now perform updates or creations using only the model and reference. example :

{
  "controller": "device-manager/assets",
  "action": "upsert",
  "engineId": "engine-ayse",
  "body": {
    "model": "Container",
    "reference": "linked1",
    "metadata": {
      "weight": 12,
      "height": 11
    }
  }
}

How should this be manually tested?

see above the api example