Add streaming support to the fedora client

Resolves: https://jira.duraspace.org/browse/FCREPO-1255
Add FedoraClient unit tests
- Refactor unit tests to use mockito and act more like UT rather than IT

Resolves: https://jira.duraspace.org/browse/FCREPO-1265
added support for dynamic transform endpoints
rebased changes from master; added tests