Investigate solr-ocrhighlighting

[saracarl]

The Polish transcription platform uses this for doing db based searches (Not solr) and highlight using bounding boxes.

Combine with Ben's ocr merging script?

[benwbrum]

See also this example of OCR highlighting using @jbaiter's code: https://dbmdz.github.io/solr-ocrhighlighting/0.8.3/example/