* Fix deprecations around ListenableFuture
SF has deprecated a `ListenableFuture` and API around it
* Migrate to `CompletableFuture` everywhere a `ListenableFuture` has been used
* Suppress a deprecation for `ListenableFuture` keeping the functionality until the next version
* Resolve deprecations nad removals from the latest Spring for Apache Kafka
* Fix documentation for the `ListenableFuture` in favor of `CompletableFuture`
NOTE: the AMQP module is left as is until `ListenableFuture` deprecation is resolved in Spring AMQP
* * Restore some `ListenableFuture` test for messaging gateway
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