* Improve JavaDocs for `BaseIntegrationFlowDefinition` with renaming `payloadType` param to `expectedType` since it can also be as a `Message.class`, not only type for the payload. * Add JavaDoc for `LambdaMessageProcessor` ctor
* Improve JavaDocs for `BaseIntegrationFlowDefinition` with renaming `payloadType` param to `expectedType` since it can also be as a `Message.class`, not only type for the payload. * Add JavaDoc for `LambdaMessageProcessor` ctor