Update citation counts from s3
This MR adds a start up task to ingest citation_update.json
files from S3 and thus update the citation counts in Elasticsearch. It also updates the `s3-ingests task to carry out citation count updates after metadata ingestion.
This relies on citation_update.json
files in the following format:
{"message": [["set", "10.1109/INTMAG.1998.742214", "is-cited-by-count", 100]]}