INT-2426: Add `Idempotent Receiver` EIP

JIRA: https://jira.spring.io/browse/INT-2426

INT-2426: pushed `final` modifier fix for Java 6 compatibility

INT-2426: Rework logic to the `MetadataStore`

INT-2426: `IdempotentReceiver` -> `IdempotentReceiverInterceptor`

* Move `Idempotent Filtering` logic to the `IdempotentReceiverInterceptor`, which should be applied as a regular
AOP `Advice` to the `MessageHandler#handleMessage`
* Provide an xml component `<idempotent-receiver>`
* Introduce `IdempotentReceiverAutoProxyCreator` to get deal with `IdempotentReceiverInterceptor` and `MessageHandler`s.
The `Proxying` logic is based on the mapping between interceptor and `consumer endpoint` `ids`
* Introduce `MetadataStoreSelector` along side with `MetadataKeyStrategy` and `ExpressionMetadataKeyStrategy` implementation

INT-2426: Introduce `IdempotentReceiver` annotation

Add `IdempotentReceiverIntegrationTests` in the JMX module to be sure that all proxying works well.

INT-2426: Polishing according PR comments

* Rename `IdempotentReceiverAutoProxyCreatorInitializer`
* Add support for several `IRI` for the one `MH`
* Polishing JavaDocs

INT-2426: Add `What's New` note

Doc Polishing.

More Doc Polishing

Use Timestamp (hex) instead of Id for Value

Facilitate cleanup.