Remove hardcoded vocab references

[justinlittman]

For example, http://cocina.sul.stanford.edu/models/image.jsonld should be replaced with Cocina::Models::Vocab.image.

Hardcoding in code and/or specs can be found in:

• [x] cocina models
• [x] dor-services-app
• [x] google books
• [x] h2
• [x] dor_indexing_app
• [x] was-registrar-app
• [x] argo
• [x] dor-services-client
• [x] sdr api
• [x] infra integration tests