Implements the DuplicationPolicyManager as part of: https://jira.duraspace.org/browse/DPS-15
Adds tests for both DuplicationPolicyRepo classes.
Adds an integration test to test the DuplicationPolicyManager against S3.
Updates the DuraStoreTaskProducer to use the completed DuplicationPolicyManager. Completes https://jira.duraspace.org/browse/DPS-15.