- custom fields: update namespace values
- tokens: make RAT subject schema configurable
- services: handle no-value DOI for links
- deposit-ui: use "vnd.inveniordm.v1+json" always
- access: serialize "owned_by" field
- resources: add "x-bibtex" record serialization
- resources: make record serializers configurable
- schema: expose checksum and file ID
- services: make record/draft API classes configurable