Add ability to populate fields on media

[mjordan]

Thanks to @dannylamb's patience on IRC, I got this working:

curl -v -u admin:islandora -H "Content-Type: application/json" -X PATCH --data-binary @my.json "http://localhost:8000/media/17?_format=json"

where my.json is

{"bundle": [{"target_id":"web_content","target_type":"media_bundle"}], "field_premis_event": [{"value":"Hi there."}]}

[mjordan]

The syntax for this has probably been obsoleted.