Add digital object ID to data source API objects
Objects currently look like this:
{
"directory_id": 2,
"path_str": "/bigdata/telbe/2018/12.06.2018",
"description": "",
"label": "First Day",
"login": 80,
"projects": [
19
],
"persistent_id": "https://hdl.handle.net/20.500.12865/HELIPORT.data_source.174"
}
They should also contain the digital object ID.