create data version

// api post content
// url /api/control_versions/data_control_version/

// request
{
    "raw_data": {"blah": "blah"},
    "schema_version_id": 1,
    "data_version_id": null,
    "content_type": "course",
    "content_id": null
}

// response
{
    "data_version_id": 1,
    "version_number": 0.1
}