When the placeholder for an thumbnail, which is at a subpath
[INSTANTIATION_ID]/derived is created before the placeholder for the
instantiation itself, this leads to errors during the ingest, because
fedora creates a pairtree node for each part in a path. Pairtree nodes
can't hold metadata themselves.

Memo 669: improve mimetype handling

See merge request !11

Use RDFDataMgr interface instead of model writer.
Replace constants with variables.

Set required envvars

See merge request !10

MEMO-774: adapt to new import workflow

See merge request !9

MEMO-734: Update fedora client to version 0.6.2

See merge request !8

MEMO-740: Set max.poll.records to 10

See merge request !7

The IngestService needs more time if a lot of binary resources need to be ingested. It then can't commit the read messages on the next poll. By setting a lower limit for max.poll.records the next poll on the Kafka topic should occur before the default max.poll.interval.ms of 5 minutes has expired.

MEMO-733: improve reporting

See merge request !6

MEMO-635: Update FedoraClient to version 0.6.1

See merge request !5