Remove unused methods from core model classes

- Remove unused FedoraObject#getName
- Replace #getModels with #hasType check
- Remove unused setContent(byte[])
- Remove Datastream#getDsId
- Remove Datastream#getObject
- Remove unused FedoraObjectImpl constructor
- Remove unused FedoraResource#getSize
- Remove unused getDatastreamNode
- Remove getSize
- Remove getDatastreamNode
- Remove unused GraphStoreStreamingOutput constructors.
- Remove unused JcrRdfTools methods
- Remove NodeService#getObjectNames

Resolves: https://www.pivotaltracker.com/story/show/78815814