Added FileStore implementation of DataStore interface, and abstract test class.
partial implementation of SecurityConfigurationMapping data store. Shows how data store might be used to persist keys using DataStore api.
changed SCM store to a LocalKeyStore that currently handles storing and retrieving PrivateKey from a DataStore.
Added unit tests for key storage and retrieval
Merge pull request #3 from kryptnostic/feature/client-persistence

Feature/client persistence