[TENE-891] Reindex flow fixup

reindexing now involves the following: when the modification time is the same in both the database record and the Solr document, and we want to perform a reindex to refresh the document (e.g., after changes in Solr configuration), the reindex handler creates a message for the records indexer containing a flag indicating reindexing. The records indexer, upon seeing this flag, copies the relevant fields from the document, deletes the doc, recreates it, and then inserts the copied fields back into the doc. After reindexing, the process ends and no further messages are sent to Kafka