Remove `@IntegrationComponentScan` from Boot samples
Since the latest Spring Boot utilize already `@IntegrationComponentScan` for the `@SpringBootApplication` class package, there is no reason to worry about lost `@MessagingGateway`
Reflect Kafka samples changes according latest Spring Boot fixes
* Fix compatibility after Java DSL migration to the SI Core
* Also upgrade all the JMS sample to the JMS 2.0
* Fix default `connectionFactory` bean reference to the current `jmsConnectionFactory`
* Remove unsupported JPA-1.0 Spec via `OpenJpaAutoConfiguration`, since the minimum now is JPA-2.0
* Remove non-lambda sample since minimum now is Java 8
* Rename `PromiseTest` to `MonoTest` and fix it to Reactor 3.0
* Fix `stomp-server.xml` to use proper Reactor 3.0 `eactor.util.function.Tuples` for SpEL
* Regenerate POMs
