Ensure that data that is being sent maps correctly to the nypl data model

[jmathewt]

https://docs.google.com/spreadsheets/d/1zhIJj_-_U9PpsvVSPin1IWaYIyuzk1RpbR2zpFN_ctU/edit#gid=16241468

The above link shows the mapping Matt created which is what recap-harvester is currently built on. We have to ensure that the nypl data model expects the same kind of data.

[jmathewt]

Questions:

1. How do we handle bibs/items that get deleted and update that in our system
2. When there is no valid lang code do we still mark it as null