JIRA: https://jira.spring.io/browse/INT-3770,
https://jira.spring.io/browse/INT-4107
Having `TransactionHandleMessageAdvice` we can start TX from any `MessageHandler.handleMessage()`
* Add `<transactional>` alongside with the `<request-handler-advice-chain>` for those components which produce reply
* Merge `<transactional>` and `<request-handler-advice-chain>` configuration to a single `ManagedList`
* Rework JPA `<transactional>` in favor of common solution
* Some polishing and refactoring
AbstractPollingEndpoint: avoid `new ArrayList` if we don't have `receiveOnlyAdvice`s