JIRA: https://jira.spring.io/browse/INT-4158
* Add JavaDocs
* De-Boot `JpaDslTests`
* Fix typos and generics inconsistency in the `JpaOutboundGatewayFactoryBean`
Address PR comments
* Get rid of `JpaOutboundGatewayFactoryBean` usage in the `JpaBaseOutboundEndpointSpec`
* Rework `JpaBaseOutboundEndpointSpec` and its inheritors logic to use `JpaOutboundGateway` directly
* Rename to the `JpaTests`
* Fix JavaDoc in the `IntegrationFlowDefinition`
* Do not use `jpaParameters` in the `JpaExecutor` if it is empty collection, not only null
1bba73fc06