JIRA: https://jira.spring.io/browse/INT-3883
UDP Outbound Channel Adapter is able to use given UDP Inbound Adapters
server socket (outgoing packets will have source port same as incoming
packets destination port).
* Introduce `destinationExpression` instead of hard-coded `host/port` logic in the `DatagramPacketMessageMapper`
* Make `UnicastSendingMessageHandler.destinationExpression` mutually exclusive with `host/port` pair
* Move `socketExpression` to the setter as it is absolutely different option from the `destination`
* Make `UnicastSendingMessageHandler` expressions logic based on the `requestMessage`
INT-3883 Code review fixes.
Further polishing
Polishing according PR comments
Rework the String socket address logic just to the expected `URI` style.
Accept `2016` for changed classes.
8bf8caa22e