Refactor NYPL script to use ProviderDataIngester class (#630)

* Refactor NYPL script to use DataIngester class
* Use topics as tags
* Fix getting the preferred image and lint
* Add a get_value_from_dict_or_list helper
* Add docs, clean up type_of_resource code
* Refactor get_value_from_dict_or_list
* Move Variable retrieval to __init__
* Add a test for get_value_from_dict_or_list

Signed-off-by: Olga Bulat <obulat@gmail.com>
Co-authored-by: Madison Swain-Bowden <bowdenm@spu.edu>