Remove Trusted payload, credential map for authenticating connector sources

With TEEID-833 the engine will be deployed to a container and TEIID-199 implements the JAAS based authentication. In the container environment the security credentials are passed contextually to the working thread where they can be accessed. So, the custom home grown solutions like trusted payload and credential mapping are no longer needed.

Make sure that "ConnectorContext" exposes the necessary information for the security.