Support specifying kinesis endpoint in debezium server

Currently AWS doesn't provide a way to specify an endpoint in a profile (https://github.com/aws/aws-cli/issues/1270).  This makes it not possible to run debezium against other kinesis endpoints without specifying a customClient (which may be it's intended use?), such as the one provided by localstack for on-prem development (https://github.com/localstack/localstack).

If a new property could be added for `debezium.sink.kinesis.endpoint` that would support this use-case.