GET /users/:id/artifacts?query=[""]
[
  {
    'id': int,
    'uri': string,
    'html_url': string,
    'title': string,
    "xref": string,
    "tracker": {
        "id": int,
        "uri": string,
        "label": string,
        "color_name": string,
        "project": {
            "id": int,
            "uri": string,
            "label": string
        }
    }
  }
]
query can be either
	- query={"assigned_to": true}
- query={"submitted_by": true}
- query={"submitted_by": true, "assigned_to": true}
The query return the same result set than "my artifacts" widget, paginated. It means it only returns "Open" artifacts (as per semantic).
As of today, the only valid value for :id is 'self', the scope can be extended in future work.